Summary

This is a part of an affine building of type A2-tilde, more precisely it is the building associated to SL(3, ℚ₂), where ℚ₂ is the field of 2-adic numbers. Here, the radius-one-neighborhood of a central chamber is visualized. I copied the design from Bram Bekker's beautiful visualization of buildings:
https://buildings.gallery/

Buildings are highly symmetric objects that show up in maths. Spherical buildings were first introduced by Jacques Tits to study finite groups of Lie type. Affine buildings were later introduced as a p-adic analogue to symmetric spaces.
Buildings consist of apartments (here these would be infinite planes), chambers (the triangles), walls, galleries, etc..
https://en.wikipedia.org/wiki/Building_(mathematics)#Overview