Good ones, y'all!
And speaking of 90-degree angles, or the illusion of such, perhaps the famous Escher-esque Penrose triangle will also be part of our new normal:
(the above pic is my quickie non-artistic digital rendition, starting from this, which I then fancied up with some Photoshop filters and coloring)
Wikipedia says of this shape:
"The tribar appears to be a solid object, made of three straight beams of square cross-section which meet pairwise at right angles at the vertices of the triangle they form. The beams may be broken, forming cubes or cuboids.
"This combination of properties cannot be realized by any three-dimensional object in ordinary Euclidean space."