Origami · folding only · Challenge · about 50 minutes

Six-Unit Modular Cube

No scissors · No glue · No adult help needed

6 × Squares of origami paper, two in each of three colors, 150 x 150 mm (6 x 6 in)

Finished

Blue dashes: valley fold (toward you). Pink dash-dot: mountain fold (away from you). Thick line with scissors: cut. Yellow: glue.

Start. Start with one square, white side up. You will fold six units exactly the same way.
1. Fold and unfold: Fold the square in half from left to right. Crease it, then unfold.
2. Valley fold: Fold the left edge in to meet the center crease.
3. Valley fold: Fold the right edge in to meet the center crease. The two edges touch in the middle.
4. Valley fold: Fold the top corner of the left flap down so its top edge lies along the left edge. Fold only this one layer.
5. Valley fold: Fold the bottom corner of the right flap up so its bottom edge lies along the right edge. Fold only this one layer.
6. Fold and unfold: Fold the top-right corner down so the top edge lies along the left edge. Crease firmly, then unfold.
7. Fold and unfold: Fold the bottom-left corner up so the bottom edge lies along the right edge. Crease firmly, then unfold.
8. Tuck: Fold the top-right corner down again on its crease and tuck it under the left flap.
9. Tuck: Fold the bottom-left corner up on its crease and tuck it under the right flap. The unit is now a slanted shape.
10. Check: Find the two pockets: the inside edges of the flaps meet in the middle. A point from another unit will slide under each flap there.
11. Turn over: Turn the unit over.
12. Fold and unfold: Fold the top point down on the line between the two side corners, so its tip touches the far corner. Crease well and unfold.
13. Fold and unfold: Fold the bottom point up the same way. Crease well and unfold. One unit is done: a square with two points.
14. Valley fold: Fold both points toward you so they stand straight up. Then turn the unit flap side up: the points hang down and the pockets are on top.
15. Check: Fold five more units the same way: two blue, two orange and two green in all.
16. Put together: Slide a point of the blue unit into a pocket of the orange unit: over its folded triangle and under its flap.
17. Put together: Add a green unit at the front. Its point goes into the blue unit, and the orange unit's point goes into the green unit.
18. Put together: Add the other orange, green and blue units on the far sides the same way. Matching colors sit opposite each other.
19. Push: Press gently on each face so every point slides all the way into its pocket.

If something goes wrong

A point will not go into the pocket. Check that it slides over the folded triangle and under the flap, not under the whole unit. Open the flap slightly with a fingertip.
The units do not line up and the cube has gaps. All six squares must be the same size, and every crease must be sharp. Refold any unit whose points are uneven.
The last unit is hard to fit. Loosen the units next to it a little, put both of its points in their pockets halfway, then push them in together.
The cube falls apart. The points need to go all the way in. Press each face gently toward the middle until the edges are straight.