Missing Square Puzzle (SOLUTION)
Although this puzzle looks like a glitch in the matrix, this is actually an optical illusion. The triangles have slightly different slopes that can't easily be detected by the human eye. The smaller blue triangle has a bigger slope than the bigger red triangle. This means that when it is placed on the bottom, there will be a missing area present, in this case an additional square. You can see this more clearly by exaggerating the slopes!
You can learn more about this puzzle here: https://en.wikipedia.org/wiki/Missing_square_puzzle
This website allows you to play around with the triangle pieces yourself: https://mathigon.org/task/currys-paradox
Check out the puzzle (without the solution) by clicking here!