Shiv Shankar Dayal schrieb am 28.08.2024 um 12:23:
I don't know where you found the code, but the answer to "What is (0, r) rotated (a *i) doing?" is that it takes the point (0,r) and rotates it a*i degrees.
I do not understand the concept of rotating a point. It is rotated with respect to what reference?
You rotate around a point with the x and y coordinates 0. The blue dot shows the point with the coordinates 0. The green dot is rotated around this point. \starttext \startMPcode drawdot (0,0) withpen pencircle scaled 5mm withcolor blue; draw fullsquare scaled (4cm) withcolor red; \stopMPcode \startMPcode drawdot (0,0) withpen pencircle scaled 5mm withcolor blue; drawdot (1.5cm,0) withpen pencircle scaled 5mm withcolor green; draw fullsquare scaled (4cm) withcolor red; \stopMPcode \startMPcode drawdot (0,0) withpen pencircle scaled 5mm withcolor blue; drawdot (1.5cm,0) rotated (30) withpen pencircle scaled 5mm withcolor green; draw fullsquare scaled (4cm) withcolor red; \stopMPcode \startMPcode drawdot (0,0) withpen pencircle scaled 5mm withcolor blue; drawdot (1.5cm,0) rotated (60) withpen pencircle scaled 5mm withcolor green; draw fullsquare scaled (4cm) withcolor red; \stopMPcode \startMPcode drawdot (0,0) withpen pencircle scaled 5mm withcolor blue; drawdot (1.5cm,0) rotated (90) withpen pencircle scaled 5mm withcolor green; draw fullsquare scaled (4cm) withcolor red; \stopMPcode \stoptext Wolfgang