Miegakure Bypasses Solid Barriers via Fourth Spatial Dimension Axis

[mtbdesignworks {Miegakure, 4D Toys}]

Traversing barriers through higher dimensions does not penetrate solid matter, but circumvents obstacles by shifting along a perpendicular axis into parallel three-dimensional slices.

AI-assisted summary of How to walk through walls using the 4th Dimension [Miegakure: a 4D game] — original source. Check the original for full context.

Source published: 2014-08-27

Key ideas

Miegakure models a true fourth dimension of space rather than time, allowing players to navigate a mathematically correct 4D environment. (0:08)
Walking 'through' a solid wall using a fourth spatial dimension is geometrically sidestepping around the obstacle along a perpendicular axis. (0:08)
The apparent visual warping when rotating into higher dimensions is simply viewing cross-sectional slices of rigid objects, directly analogous to MRI scans. (1:41)
By shifting into an adjacent 3D slice of space where an obstacle does not exist, a traveler can advance forward and step back to emerge on the obstacle's far side. (1:41)

Detailed notes

## Background Published by mtbdesignworks on YouTube on August 27, 2014, this video demonstrates the four-dimensional puzzle-platformer Miegakure. The description explains that the game models a true fourth dimension of space rather than time, showing how moving along this extra coordinate allows a player to bypass solid obstacles by walking around them in higher-dimensional space.

## TL;DR The video demonstrates how navigating a fourth spatial dimension allows a character to bypass an impassable wall in Miegakure. To explain this concept intuitively, the narrator constructs an analogy of a two-dimensional character facing a wall on a flat plane who sidesteps into the third dimension to walk around the barrier. Applying the same geometric principle to higher dimensions, rotating between cross-sections reveals adjacent 3D slices of the world, comparable to MRI scan layers. By stepping along the fourth coordinate axis where the obstacle does not exist, the player easily moves past the blockage and steps back into the original environment on the other side.

## Atmosphere & style The presentation carries a calm, cerebral, and methodical tone, resembling an interactive math lecture brought to life through elegant software. The narrator speaks with a gentle, patient clarity that demystifies mind-bending spatial concepts, guiding the viewer from intuitive Flatland analogies to complex 4D rotations. Watching the world shift and re-slice creates a quiet sense of wonder and intellectual revelation as an apparently impossible feat turns out to be simple geometry.

## Bulletin - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) Miegakure models a true fourth dimension of space rather than time, allowing players to navigate a mathematically correct 4D environment. - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) Walking 'through' a solid wall using a fourth spatial dimension is geometrically sidestepping around the obstacle along a perpendicular axis. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) The apparent visual warping when rotating into higher dimensions is simply viewing cross-sectional slices of rigid objects, directly analogous to MRI scans. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) By shifting into an adjacent 3D slice of space where an obstacle does not exist, a traveler can advance forward and step back to emerge on the obstacle's far side.

## Key takeaways - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) In Miegakure, the fourth dimension is a spatial coordinate rather than time, making the game effectively 5D if time is counted. - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) When confronted with an impassable wall in standard 3D space, turning into the fourth spatial dimension provides an alternative path. - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) Moving along the fourth axis replaces the blocking wall with an adjacent environment containing only rubble that extends into that dimension. - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) A lower-dimensional analogy of a 2D Flatland character illustrates how turning into a third spatial dimension allows bypassing an otherwise insurmountable 2D barrier. - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) Sidestepping into depth remaps standard planar movement controls to navigate along the third dimension. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) To an observer confined to a lower dimension, objects appear to warp and deform during dimension rotation, though the higher-dimensional geometry remains entirely static. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) Lower-dimensional perspectives of higher-dimensional objects function identically to planar cross-sections produced by MRI machines. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) The same mathematical principles enable a 3D being to pivot controls along a fourth coordinate axis to enter an adjacent 3D cross-section. - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) Advancing forward in an adjacent 3D slice avoids the obstacle, after which rotating and stepping back returns the player to the original 3D world on the other side. - To an outside 3D observer, a person utilizing the fourth dimension would simply vanish and subsequently reappear on the other side of the wall.

## Detailed walkthrough ### [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) The 4D Problem and the 2D Analogy

*Miegakure* is introduced as a four-dimensional game where space itself contains a fourth dimension, rather than treating time as the fourth coordinate. The central premise is demonstrating what it would genuinely look like if someone were able to navigate through a solid barrier using spatial movement along this extra dimension. In an opening scenario, the player encounters a massive wall: it is impossible to jump over it, and there is no way to walk around it within ordinary space. The narrator asks: “So I thought I would show what it would actually look like if you could walk through walls using the fourth dimension, and in the process explain what the fourth dimension is.” When the player turns to face along the fourth dimension, walks forward, and then turns back, the wall vanishes entirely, replaced by a mound of rubble resting in a desert environment.

To make this intuitive, the narrator steps back to examine a lower-dimensional analogy involving a flat, two-dimensional character facing a similar blockage on a 2D plane. In Flatland-style 2D space, the character cannot jump over the obstacle or walk around it. However, if the underlying reality is actually three-dimensional and the character is merely restricted to moving along a single plane, sidestepping into the third dimension becomes possible. By pressing a button to turn sideways into depth, left-and-right controls are remapped to navigate along the third dimension. Moving along this new axis and rotating back leaves the character in a parallel slice of the world where the barrier is gone, replaced only by fallen rubble that spilled into the third dimension, allowing effortless passage past the obstacle before turning sideways once more to re-enter the starting grass plane.

```mermaid flowchart TD accTitle: 2D to 3D Analogy Flow accDescr: Step-by-step process of a 2D character bypassing a barrier using a third spatial dimension. subgraph Initial["Initial Position"] A["Blocked by 2D wall"] --> B["Press button to turn sideways"] end subgraph ThirdDim["Third Dimension Shift"] B --> C["Move along 3rd dimension axis"] C --> D["Press button to face forward"] end subgraph Parallel["Parallel Plane"] D --> E["Wall disappears / Rubble visible"] E --> F["Walk safely past obstacle"] F --> G["Turn sideways & step back to original plane"] end ```

[01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 2D Slices and Navigating 4D Space

Because the 2D character cannot directly visualize a full 3D environment, the visual transformation looks bizarre from an internal point of view. As the character turns sideways, the surrounding objects appear to warp and reshape dynamically. The narrator clarifies: “He might think the world is deforming, but it's just what it would look like if you took 2D slices of a 3D object, like images produced by an MRI machine, for example.” The reality itself remains rigid and static; only the cross-sectional angle of observation changes. When situated further along the third dimension within the desert slice, the tall wall is absent from view, leaving only the scattered rubble visible until the character shifts perspective sideways once more to bridge back into the grassy plane.

Returning to what the narrator terms “thicker problems,” the exact same mathematical logic applies to human beings if our universe possesses four spatial dimensions while our perception is restricted to a three-dimensional slice. By pressing a control button to pivot into the fourth dimension, standard spatial movement shifts along the fourth coordinate axis. Stepping forward in this orientation and toggling perspective back deposits the player into an adjacent 3D cross-section of the 4D world. In this adjacent space, the blocking wall is no longer present directly ahead—only rubble extending into the fourth dimension remains—permitting the character to walk straight forward past the obstacle. Pivoting once more into the fourth dimension and stepping back returns the character to their home 3D world on the other side of the obstacle. The narrator concludes: “And this is how you walk through walls using the fourth dimension.”

- The apparent deformation seen when rotating between dimensions is merely a sequence of planar cross-sections, identical to how an MRI scan visualizes a 3D organ slice-by-slice. - Moving through an obstacle in higher-dimensional geometry is technically not walking *through* the matter itself, but rather sidestepping *around* it via an axis perpendicular to standard 3D space.

## Mentioned Miegakure, Marc ten Bosch, mtbdesignworks, Flatland, 4D Toys, Steam, Patreon, Twitter

## Video description An explanation of how walking through walls would actually look like if you could move in 4D, using the 4D video-game Miegakure (http://miegakure.com) For more details, see this blog post: http://marctenbosch.com/news/2014/08/new-trailer-how-to-walk-through-walls-using-the-fourth-dimension

* We will make more videos explaining the fourth dimension using the game. Subscribe to the channel if you are interested!

* In this game the fourth dimension is not time, it is a fourth dimension of space. So if you count time the game is a 5D game. It is a correct representation of a fourth spatial dimension.

* Yeah it's actually "around" walls, not "through!"

* There are *infinitely* many 3D worlds stacked on top of each other, even if in the introductory Wall Level the ground texture makes it seem like there are only two. A more complex example is the shape at the beginning of the trailer, which is a true 4D shape called the 120 Cell, as explained here: http://marctenbosch.com/news/2014/04/what-is-that-shape-at-the-end-of-the-trailer-hd-screenshot/

* From the perspective of a regular 3D observer standing next to the wall the player character would suddenly disappear, and a few moments later reappear on the other side of the wall.

* See also: Flatland (https://en.wikipedia.org/wiki/Flatland)

⦿ Support us on Patreon: https://www.patreon.com/marctenbosch ⦿ Wishlist Miegakure on Steam: https://store.steampowered.com/app/355750/Miegakure ⦿ Buy 4D Toys on iOS: http://4dtoys.com/ios ⦿ Buy 4D Toys on Steam: http://4dtoys.com/steam ⦿ Mailing list: https://marctenbosch.com/mailing-lists ⦿ Blog: https://marctenbosch.com/news ⦿ Twitter: https://twitter.com/MiegakureGame

[Source](https://www.youtube.com/watch?v=9yW--eQaA2I)

中文简报

《Miegakure》借助第四空间维度轴绕过实体障碍通过更高维度跨越障碍物并非穿透实体物质，而是沿着一条垂直轴平移进入平行的三维切片，从而绕开障碍。视频展示了在《Miegakure》中操控第四空间维度如何让角色绕过一堵无法穿过的墙。为了直观地解释这一概念，解说者打了个比方：平面上的二维角色在面对一堵墙时，可以向第三维度迈出一步，从而绕开障碍物前行。将相同的几何原理应用到更高维度时，在截面之间旋转即可展现出相邻的三维世界切片，这与核磁共振（MRI）扫描层十分相似。通过踏入不存在该障碍物的第四坐标轴，玩家可以轻松穿过堵塞处，并在另一侧重新切回原本的环境中。《Miegakure》模拟的是真正的第四空间维度而非时间维度，允许玩家在数学上严谨的四维环境中移动探索。 (0:08) 利用第四空间维度“穿过”实体墙，在几何本质上是沿着垂直轴侧步绕过障碍物。 (0:08) 向更高维度旋转时看到的视觉形变，实际上只是刚性物体的横截面切片，这与核磁共振（MRI）扫描完全类似。 (1:41) 通过平移进入不存在障碍物的相邻三维空间切片，行进者可以向前移动并切回原维度，从而出现在障碍物的另一侧。 (1:41)

Detailed notes — zh

## Background 该视频由频道 mtbdesignworks 于 2014 年 8 月 27 日发布在 YouTube 上。视频以独立四维游戏《Miegakure》为载体，展示了如果人类能够借助额外的第四空间维度移动，在现实中看起来宛如“穿墙”的现象实际上是如何发生的。 ## TL;DR 视频通过游戏《Miegakure》深入浅出地解释了第四空间维度的几何原理。解说首先通过《平面国》（Flatland）式的降维类比，说明一个困在二维平面内的角色如何通过转向第三维度、从侧面迈步绕过障碍，并以核磁共振（MRI）切片的概念解释观察者看到的视角变化。随后将该逻辑升维至现实三维空间，证明面对三维高墙时，玩家实际上是转向并漫步穿行于第四维度，从而在三维观察者眼中呈现出“凭空消失并在墙后重现”的穿墙奇观，但其本质是高维度的侧向绕行而非物理穿透。 ## Atmosphere & style 视频展现出一种沉静、严谨且充满知性美感的科普氛围，配乐与画面呈现出一种空灵而深邃的禅意。解说的语调平缓笃定，没有花哨浮夸的噱头，而是像一位耐心的数学导师通过逐步拆解与推导，引领观众打破固有的三维知觉局限。观看过程带有一种豁然开朗的几何启迪感，让观众在直观感受维度切片转换的奇妙视觉时，经历一场兼具哲学思辨与空间想象的智力震撼。 ## Bulletin - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 独立游戏《Miegakure》展示了四维空间的真实物理机制，游戏中的第四维度并非时间，而是第四个纯粹的空间维度。 - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 在四维几何中，“穿墙”在本质上并非直接撞击或穿透实体，而是利用第四个自由度绕开障碍（walk around the wall）。 - [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 通过“平面国”（Flatland）的二维与三维类比，三维世界中看似不可逾越的障碍，在高维观察者眼中仅需侧向迈出一步即可避开。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 高维物体在低维视角下的形变与消失，类似于核磁共振（MRI）的逐层断层切片扫描，世界本身并未改变，仅仅是观察角度发生了旋转。 ## Key takeaways - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 游戏《Miegakure》基于真实的第四空间维度开发，若将时间维度计入则构成了五维系统。 - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 在三维空间中被高墙阻隔且无法翻越时，可通过转向并沿第四空间维度移动来绕过该阻碍。 - [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 玩家沿第四维度完成位移并切回原朝向后，原先高大的墙体在视野中消失，取而代之的是散落碎石的沙漠地貌。 - [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 借助二维“平面国”思维模型可以更轻松地理解高维运作：二维扁平生物面对二维障碍墙时在自身平面内无路可走。 - [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 在三维观察者眼中，二维角色只需向第三维度的侧向迈步（sidestepping）即可绕过障碍。 - [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 二维角色在游戏中按下按键转向侧方后，其屏幕水平移动轴即转变为在第三维度深度轴上的移动。 - [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 沿第三维度行走数步后转回初始视角，角色实际上已进入沿第三维度分布的另一个平行切片世界。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 低维角色在高维切片中移动时，视野的变化类似于MRI逐层断层扫描图像，物体形变只是三维横截面的变化展示。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 客观物理世界并未发生扭曲或改动，低维生物主观感知到的剧烈变化纯粹是因为从不同角度观测高维切片。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 将低维模型映射至现实：若现实世界是四维空间的一个三维超平面切片，三维角色便可借助第四维度进行侧向位移。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 在第四维度侧移后再返回，原本阻隔前路的三维高墙会退至四维切片的侧方，使前方路径畅通无阻。 - [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 对于无法感知第四维度的常规三维观察者而言，利用四维位移的角色看起来就如同突然凭空消失又在墙后凭空出现。 ## Detailed walkthrough ### [00:08](https://www.youtube.com/watch?v=9yW--eQaA2I&t=8s) 四维空间中的“穿墙”假象与基本概念解说者首先介绍了独立游戏《Miegakure》，指出这是一款真正的四维游戏，其中包含一个第四空间维度。为了向大众阐释第四维度的运作机制，视频的核心目标就是展示如果人类能够借助第四空间维度行动，所谓“穿墙”在视觉和物理上究竟会以何种方式呈现。假设玩家在一个三维空间中遇到了一堵高墙，想要到达墙的另一侧，但既无法直接跳过去，也无法绕着它走过去。解说者提出了一个假设：“如果这个世界不仅限于此呢……如果你可以直接在第四维度里绕过这堵墙会怎样？”（“what if could just walk around the wall in the fourth dimension?”）。按照游戏的操作逻辑，玩家需要转向面朝第四维度的方向，沿着第四维度移动几步，然后再转回原本的视角。此时玩家会惊奇地发现，眼前的整堵高墙居然彻底消失了，取而代之的是一片沙漠正中央散落的一堆瓦砾碎石。为了深入解释这一视觉奇观背后的数学与几何原理，解说者暂停了三维操作，转向更易理解的降维类比。 ```mermaid flowchart LR accTitle: 4D Walkaround Concept accDescr: Diagram showing how a player turns into the 4th dimension to bypass a 3D wall subgraph S1["原三维视角"] A["面前受阻于一堵高墙"] end subgraph S2["四维侧移"] B["转向第四空间维度"] C["沿第四维度直行走过阻碍"] end subgraph S3["切回原三维空间"] D["转回原本方向"] E["墙壁消失，仅见散落碎石"] end A --> B B --> C C --> D D --> E ``` --- ### [00:42](https://www.youtube.com/watch?v=9yW--eQaA2I&t=42s) 二维降维类比：平面的困境与三维侧移为了让观众直观理解高维度的运作机制，解说者构建了一个低维度的“平面国”（Flatland）式思维实验：假设你是一个身处二维平面的角色，正被前方的一堵二维墙壁挡住去路。在这个二维世界里，你既跳不过去，也没有其他多余的维度可以绕行，基本处于无路可走的境地。随后解说者抛出核心设问：“如果这个世界实际上是三维的，而你只是一个只能在二维平面内活动的扁平角色呢？”（“What if the world was actually 3D, and you were just a 2D flat character that could only move inside a 2D plane?”）。在三维观察者眼中，解决这道墙极其简单，只要从侧面迈出一步（sidestepping）即可绕过。但受困于平面的二维生物该如何执行这一动作？答案是在游戏中按下一个按键完成“侧向转向”。转向完成后，屏幕上的左右移动便被赋予了全新的物理含义：它不再代表原本平面的左右，而是代表在“第三维度”上平移。角色沿着第三维度走上几步，再次按下按钮转回原本的朝向，此时角色实际上已经置身于沿第三维度延伸的一个“平行世界”或不同切片之中。在新的切片里，原本横亘在眼前的墙壁已经移到了侧方，玩家可以直接大步穿行而过。解说者还特别指出场景中的细节，在第三维度的这个切片上散落着碎石，就像是墙体在第三维度崩塌掉落的一样。最后，角色再次侧向转向并走回几步，即可重返最初的草地世界。 - 二维角色在平面内遭遇墙壁时，没有任何常规移动途径能够翻越或绕开障碍。 - 按下旋转键后，原本的水平移动轴转换成了第三维度的深度轴。 - 再次切回正面视角时，角色处于第三维度更远处的切片空间，原本的整堵墙在当前位置不复存在，显露出可通行的空隙与废墟碎石。 --- ### [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) 观察者视角、断层切片与重返四维由于二维角色本身缺乏对三维空间的立体感知，当他侧向旋转并在三维世界切片中穿行时，其主观视觉体验极具迷惑性。解说者解释道，二维角色在旋转时可能会误以为整个世界正在发生扭曲形变，但本质上这只是用二维平面切割三维物体所产生的横截面变化，正如核磁共振成像（MRI）设备逐层扫描生成切片图像一样：“世界本身并没有改变，只是从不同的方向被观察而已。”（“The world isn't changing, it's just being seen from different directions.”）。当二维角色移动到第三维度的沙漠区域时，他看不到原本高墙的截面，只能看到碎石的截面；而切换到侧向视角时，他能清晰地跨越各个切片世界，一路走回最初的草地世界。随后，解说者将思维模型切回我们所处的现实维度，探讨“更厚重的问题”（thicker problems）：如果我们的现实世界实际上拥有四个空间维度，而我们仅仅只能感知其中的三个维度呢？换言之，如果我们就是生活在四维空间中某个“三维切片超平面”上的生物，穿墙的原理便完全相同： - 面对三维高墙时，按下按键转向侧方的第四维度； - 此时空间中的横向移动代表沿着“第四空间维度”行进； - 行走数步后再次按下按钮恢复原视角，玩家已抵达第四维度更远处的平行三维世界切片； - 原本的三维墙壁不再阻挡前方，而是偏移到了四维切片的侧方，玩家可以毫无阻碍地漫步走过； - 沿第四维度穿过墙壁所在区间后，再次侧向转向并沿第四维度倒退走回，便能完美切回原本的三维空间。解说者最后总结指出，这就是所谓的“利用第四维度穿墙”，在三维普通观察者看来角色仿佛凭空消失又重新穿墙而出，但从几何实质来说，角色从未真正撞入墙体，而是利用额外的自由度从第四维度“绕开”了障碍。 ## Notable quotes > [01:41](https://www.youtube.com/watch?v=9yW--eQaA2I&t=101s) The world isn't changing, it's just being seen from different directions. — 解说者 ## Mentioned Miegakure, Marc ten Bosch, mtbdesignworks, 平面国 (Flatland), 4D Toys, 120胞体 (120 Cell), 核磁共振成像 (MRI), Steam, Patreon, iOS, YouTube ## Video description An explanation of how walking through walls would actually look like if you could move in 4D, using the 4D video-game Miegakure (http://miegakure.com) For more details, see this blog post: http://marctenbosch.com/news/2014/08/new-trailer-how-to-walk-through-walls-using-the-fourth-dimension * We will make more videos explaining the fourth dimension using the game. Subscribe to the channel if you are interested! * In this game the fourth dimension is not time, it is a fourth dimension of space. So if you count time the game is a 5D game. It is a correct representation of a fourth spatial dimension. * Yeah it's actually "around" walls, not "through!" * There are *infinitely* many 3D worlds stacked on top of each other, even if in the introductory Wall Level the ground texture makes it seem like there are only two. A more complex example is the shape at the beginning of the trailer, which is a true 4D shape called the 120 Cell, as explained here: http://marctenbosch.com/news/2014/04/what-is-that-shape-at-the-end-of-the-trailer-hd-screenshot/ * From the perspective of a regular 3D observer standing next to the wall the player character would suddenly disappear, and a few moments later reappear on the other side of the wall. * See also: Flatland (https://en.wikipedia.org/wiki/Flatland) ⦿ Support us on Patreon: https://www.patreon.com/marctenbosch ⦿ Wishlist Miegakure on Steam: https://store.steampowered.com/app/355750/Miegakure ⦿ Buy 4D Toys on iOS: http://4dtoys.com/ios ⦿ Buy 4D Toys on Steam: http://4dtoys.com/steam ⦿ Mailing list: https://marctenbosch.com/mailing-lists ⦿ Blog: https://marctenbosch.com/news ⦿ Twitter: https://twitter.com/MiegakureGame [Source](https://www.youtube.com/watch?v=9yW--eQaA2I)

Source quotes

[1:41] 解说者: The world isn't changing, it's just being seen from different directions.

Original transcript

[0:08] Miegakure is a 4D game. [0:09] A game where there is a fourth dimension of space. [0:12] So I thought I would show what it would actually look like [0:14] if you could walk through walls using the fourth dimension, [0:16] and in the process explain what the fourth dimension is. [0:22] So say you need to get to the other side of that wall, [0:25] but you can't jump over it and you can't walk around it. [0:27] But what if there was more to this world... [0:29] what if could just walk around the wall in the fourth dimension? [0:33] So you turn to face along the fourth dimension, [0:35] walk along the fourth dimension, and turn back. [0:38] You discover that the wall has disappeared, [0:40] and it's been replaced by a pile of rubble in the middle of a desert. [0:42] OK, before I continue, let me explain something first. [0:45] So say you are this 2D character [0:46] and you need to get to the other side of that wall, [0:48] but you can't jump over it and... well that's about it. [0:53] But what if there was more to this world? [0:55] What if the world was actually 3D, and you were just a 2D flat character [0:58] that could only move inside a 2D plane? [1:02] You could go past that wall by just sidestepping it, [1:04] but how do you do that, since you're stuck on a plane? [1:07] So you press a button to turn sideways, [1:10] and now, when you're moving left and right [1:12] it doesn't mean the same thing, [1:14] it actually means moving along the third dimension. [1:17] So you take a few steps, [1:19] and you press the button again to face the original way, [1:21] but now you're in a parallel world [1:23] that is further along the third dimension, [1:25] So the wall is not in front of you anymore, [1:27] it's off to the side, and you can walk right past it. [1:31] You notice that some rubble must have fallen off the wall [1:33] in the third dimension also. [1:36] You turn sideways, and take a few steps [1:38] to get back to the world you came from, and turn back. [1:41] OK, but this little character is only 2D, [1:44] so unlike us he can't see the third dimension, [1:47] so what does he see when he turns sideways? [1:49] He might think the world is deforming, [1:51] but it's just what it would look like if you took 2D slices of a 3D object, [1:55] like images produced by an MRI machine, for example. [2:03] The world isn't changing, [2:05] it's just being seen from different directions. [2:07] So when he is further along [2:09] the third dimension, down in the desert world, [2:10] he can't see the wall, but he can see the rubble. [2:15] And from the sideways perspective [2:17] he can move across worlds back into the grass world. [2:20] But back to thicker problems. [2:21] What if the world actually had four dimensions [2:23] but we could only see three? [2:25] In other words, what if we were living on a 3D plane inside a 4D world? [2:30] So you press a button to turn sideways, [2:33] and now when you're moving this way [2:35] it doesn't mean the same thing it used to mean, [2:37] it actually means moving along the fourth dimension. [2:40] So you take a few steps, [2:41] and you press the button again to face the original way, [2:44] but now you're in a parallel world [2:46] that is further along the fourth dimension, [2:48] so the wall is not in front of you anymore, but off to the side, [2:51] and you can walk right past it. [2:54] And you can notice that some rubble [2:56] must have fallen off the wall in the fourth dimension. [3:00] You turn sideways, and take a few steps [3:02] to get back to the world you came from, and turn back. [3:06] And this is how you walk through walls using the fourth dimension.