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problem
Flexi quads
A quadrilateral changes shape with the edge lengths constant. Show
the scalar product of the diagonals is constant. If the diagonals
are perpendicular in one position are they always perpendicular?

problem
Vector walk
Starting with two basic vector steps, which destinations can you reach on a vector walk?

problem
Polygon walk
Go on a vector walk and determine which points on the walk are
closest to the origin.