Upper left: 3 triangles. The two interior and the outline of both together.
Upper right: 5 triangles. 3 upright inside, 1 upside down inside, and the outline.
Lower right: 9 rectangles. The 4 inside square plus the one outline of the whole square = 5. Then the upper two squares together make a rectangle and the lower two squares make a rectangle. (5 + 2 = 7) Lastly the left inner 2 squares make a rectangle and the right inner 2 squares make a rectangle. (7 + 2 = 9)
Lower left: each one is 4 times larger than the previous.
Hope it helps & hope I didn’t miss any.
