See Section 26.15.8 for checking for squares in 2D geometry.
The is_square command determines whether or not a geometric object is a square.
| is_square([2,2,0],[-2,2,0],[-2,-2,0],[2,-2,0]) | 
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| S:=square([0,0,0],[2,0,0],[0,0,1]); is_square(S) | 
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| is_square([2,2,0],[-2,2,0],[-2,-1,0],[2,-1,0]) | 
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