Beige Shapes 
Pink and Orange Diamonds
https://www.sciencedirect.com/science/article/pii/S0896627309002396
https://www.naeyc.org/resources/pubs/tyc/apr2014/discovering-shapes-and-space-preschool
https://www.babame.com/importance-of-learning-shapes-and-colours.html
https://www.mensaforkids.org/teach/lesson-plans/exploring-shapes/
Brick Wall 
Colored Triangles