The 120 pcs box is tightly packed. Here is an illustrated guide:

It's convenient for children to put the pieces back in the box after playing. 😀

Step 1

Place 2 large square pieces flat in the corners.

Step 2

Stack 10 square pieces together and place them on top of the large square pieces.

Step 3

Repeat the same process with another set of 10 square pieces. In total,

stack 4 sets of square pieces (40 pieces) on top of the large square pieces.

Step 4

Place the remaining pieces, except for the equilateral triangles and big triangles,

in an upright position in the left empty space.

Step 5

Insert 8 big triangles (stacked in sets of 4) into the lower gap.

Step 6

Insert 12 equilateral triangles (stacked in sets of 6) as shown below:

Completed! 👏