42 lines
937 B
Plaintext
42 lines
937 B
Plaintext
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& Lesson 12: c_ngon
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& Clayson walks you through this step by step
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& It's just high school trigonometry
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& But that probably strikes terror into the hearts of PhD students in the humanities
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& So I've adapted his solution.
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& He walks you carefully through it on pp. 24-31.
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fn ngon! (sides, size) -> repeat sides {
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fd! (size)
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rt! (inv (sides))
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}
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fn c_ngon! (sides, radius) -> {
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& first, some fancy trigonometry
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& don't read this if you don't want to
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& but: there are two hard problems here
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& how far to turn before drawing the ngon
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& and how long each side should be to fit inside the radius
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let entry_turn = sub (
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0.5
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mult (
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0.25
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sub (sides, 2)
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inv (sides)))
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let side_length = mult (
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2
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radius
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sin (div (0.5, sides)))
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& now that we have the math: what do we need the turtle to do
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pu! ()
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fd! (radius)
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pd! ()
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rt! (entry_turn)
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ngon! (sides, side_length)
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lt! (entry_turn)
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pu! ()
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bk! (radius)
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pd! ()
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}
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