Those particular rhombuses are typically known as "squares"
https://www.youtube.com/watch?v=bccNH82DIo0
https://www.youtube.com/watch?v=hF_2yHXD_CU
(and...neat puzzle...nice job, creator!)
So rather than 3 rhombuses – or 3 squares – perhaps it's 3 squares of 1 square and 1 rectangle. (Perhaps the positions of the puzzle pieces make it such that it truly is 3 squares)!