The goal is to entirely cover the white rectangle
with the seven colored tangrams.
A tangram can be dragged, flipped with a double left click,
and rotated 45 degrees either clockwise with a middle click
or counterclockwise with a right click.
Tangrams' corners attract each other when they are near.
This feature, which eases the placement of tangrams,
may preclude some small movements that would put
two corners a few pixels apart.