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Quadrilateral assignments consist in a list of four variable names followed by
either parallelogram
, rectangle
or square
, and some
optional parameters.
Example: A B C D parallelogram 6, 3, 60°
In the following, we will use letter x for the first side of the quadrilateral, i.e. the segment joining the first and the second vertices, y for the fourth side, i.e. the segment joining the first and the fourth vertices, u and v the corresponding vectors. Likewise, we will use letter a for the first angle, and b for the angular direction of the first side.
In quadrilateral assignments, one, two or three vertices may be predefined. Like
with triangular assignments, if no vertices are predefined then the first
variable is set to the origin of the implicit coordinate system. The direction
of the first side is horizontal unless specified by an angular value at the end
of the parameter list. If two vertices are predefined then the parameters
giving the length and the orientation of the first side have to be omitted. If
three vertices are predefined then only parallelogram
is valid.
parallelogram { x, } y, a { , b }
rectangle { x, } y, { , b }
square { x { , b } }
Default assignments, i.e. assignments without parameters, are only valid with at most one predefined vertex.
parallelogram
Assigns a parallelogram such as x = 5, y = 4 and a = 75°.
rectangle
Assigns a golden rectangle such as x = 6.
square
Assigns a square such as x = 4.
This assignment is only valid with at most one predefined vertex.
parallelogram u, v, a
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