Our brain reconstructs the 3D scene based on the angles perceived by both eyes. So (under some natural assumptions) a human in hyperbolic space would perceive it as the Beltrami-Klein ellipsoid model -- their eyes would be at the foci of this ellipsoid!
Note that, in the picture in [2/3], for clarity, the distance between foci was much larger than the distance between the eyes of the Princess. Here is a picture that is more accurate to the size of HyperRogue characters. The cutting plane is more "flat" and the perceived shape of hyperbolic space is closer to a B-K ball than obvious ellipsoid.
(This was inspired by @theking's 2019 post https://www.reddit.com/r/Hyperrogue/comments/aq4i7k/euclidean_depth_perception_in_the_hyperbolic_plane/ abut what hyperbolic space looks like, and the "stretched B-K" result was originally proven by Magma in the HyperRogue discord -- however, Magma's proof only used continuity to show that the ellipsoid model is azimuthal in two points -- but not that they are actually foci.)
[3/3] #hyperrogue #vr #RogueViz #nonEuclidean #noneuclideanGeometry #mathart #geometry
A minor, but still quite large, update to HyperRogue!
Suggest moves after 3 incorrect attempts, grow Ivy through narrow chasms, use compasses, rulers and non-Euclidean tools in the built-in drawing tool, more intuitive touch dragging, bugfixes and more!
https://github.com/zenorogue/hyperrogue/releases/tag/v13.1l #noneuclidean #roguelike #mathart #tessellation #HyperRogue #RogueViz #noneuclideanGeometry
An aperiodic tessellation of the hyperbolic plane, found by Toimine in the #tessellations channel in the HyperRogue discord.
These tiles are equilateral, with edge length of 0.56358, which is less than the 0.56626 that was achieved by the regular {7,3} tiling (which was apparently the previous record for a tiling with equilateral convex tiles).
It is also possible to the connect two pentagons by their "bases" to obtain a funky variant of the {8,3} tiling. Then, we can play with the angles -- for "narrow" tiles, the edge length becomes even smaller, about 0.5436.
The animated visualization also shows some new cool features of the RogueViz expression parser: it can now automatically solve for the edge length which makes the tiling work for the given angle \(\alpha\)!
https://github.com/zenorogue/hyperrogue/blob/master/tessellations/sample/aperiodic_pentagons.tes
And here is the same visualization style applied to two other map projections.
Equirectangular keeps the scale constant on the equator and meridians. But the squares close to the poles are stretched.
Gall-Peters preserves the relative areas. The poles are even more stretched.
While the Mercator projection fails to preserve the relative sizes, it does map squares to (almost) squares, which made the Mercator visualization look very nice.
A yet another visualization of the distortions of the Mercator projection.
An ASCII map using the Mercator projection is projected back on a sphere. In the map, all the characters are of the same size.
Our new video!
In most of our videos, we have been playing with the non-Euclidean spaces. However, we have not played with the time dimension in them so far. In this video, we will combine spherical and hyperbolic geometry with relativistic effects.
#RogueViz #RelativeHell #mathart #NonEuclideanGeometry #RelativitySpace
Do you want the hexes on a sphere to be regular?
Or do you want them to be of the same area?
Or do you want straight lines be actually straight? (in one of two ways)
And the same idea with squares.
The animation on the left shows clearly that the shortest path is the straight line. Unbelievably, there are possible worlds where this would NOT be the case!
For example, it is not true in Discworld from Terry Pratchett's novels, which is famously a flat world. In a flat world, the shortest path is NOT a straight line!
(Based on the map of Discworld from https://www.reddit.com/r/discworld/comments/odrog0/wip_discworld_high_res_map/ )
Ported Seuphorica (Scrabble solitaire deckbuilder) to RogueViz for a more intuitive and powerful interface!
(1) Infinite square grid, with standard Seuphorica special powers. Letters E and R (inverse colors close to the gigantic EE top left) are "reversing", hence "RE" is accepted and "EE" is accepted multiple times. Note the word GEESE which uses a portal to get a multiplier for gigantic 'E' two times in a single word. "PETER" uses a mirror.
But since this is RogueViz, let us make the board geometry abstract, to have even more fun with geometry and topology!
(2) Usually, words can only go "right" and "down". In hyperbolic geometry, we have holonomy, so "right" and "down" are not globally defined. So we have to accept both directions. (Or, optionally, only accept words if they are valid both ways.)
(3) In this one, "right" and "down" are not globally defined either, but "horizontal" and "vertical" are (in a somewhat twisted way), so Seuphorica "horizontal" and "vertical" multiplier powers can work.
Although the hexagons somehow turn a horizontal word into a vertical one...
#RogueViz #NonEuclideanGeometry #mathart #noneuclidean #HyperbolicGeometry #Seuphorica #scrabble
(to be continued...)
Zeno Rogue