[up to this 3D shape]
- Start from
- Rotate 180 degrees with a valley fold the two East adjacent tiles
(the two extremal tiles in the flat 2x2 square)
- Lower the upright flap 90 degrees against the other flap
- Rotate 90 degrees the two adjacent tiles pointing down, one of them will
stack against the two stacked flaps
- End up with a 2x2 square with two stacks of two tiles in the East positions,
a stack of three tiles in the North-West position and a single tile in the South_West
position
- Open in 3D with the following hingings
- Keep the two tiles in the NE stack together
- Hinge the SE stack about the East side
- Hinge the two top tiles in the NW stack about the North side
- Hinge the two bottom tiles in the NW stack about the East side
- The resulting structure is contained in a 1x1x2 box and comprise a pair of stacked tiles
- Rotate 90 degrees a group of three mutually orthogonal tiles
- Rotate 90 degrees a newly created flap into the final shape
