turtle-tex/examples.tex at main · cao-/turtle-tex · GitHub

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\load[turtle]
%\pdfcompresslevel=0
%\pdfobjcompresslevel=0

\parindent=0pt


\def\repeat#1 #2{\fornum 1..#1 \do{#2}}

\def\turtleline #1{\line{\foreach #1\do ##1,{\bturtle ##1 \eturtle \hfil}}}

Basic sequence of turtle movements
\vskip 110pt
\bturtle
\forward 100
\right 90
\forward 150
\left 45
\back 100
\left 45
\eturtle

\bigskip
Squares and rectangles
\def\squarepiece #1 {%
    \forward #1
    \right 90
}
\def\square #1 {%
    \repeat 4 {%
        \squarepiece #1
    }}
\def\rectangle #1 #2 {%
    \repeat 2 {%
        \squarepiece #1
        \squarepiece #2
    }}

\vskip 110pt
\turtleline{\square 100, \rectangle 100 50,}

\bigskip
Some things
\def\thing {%
    \forward 20
    \right 90
    \forward 20
    \right 90
    \forward 10
    \right 90
    \forward 10
    \right 90
    \forward 20
    \right 90
    \forward 5
    \right 90
    \forward 5
    \right 90
    \forward 10
}
\def\thingone {%
    \repeat 4
        \thing
}
\def\thingtwo {%
    \repeat 9 {%
        \thing
        \right 10
        \forward 10
    }}
\def\thingthree {%
    \repeat 8 {%
        \thing
        \left 45
        \forward 20
    }}
\vskip 50pt
\turtleline{\thing, \thingone, \thingtwo, \thingthree,}

\bigskip
Circles and arcs
\def\arcr #1 #2 {%
    \repeat #2 {%
        \forward #1
        \right 1
    }}
\def\arcl #1 #2 {%
    \repeat #2 {%
        \forward #1
        \left 1
    }}
\def\circles {%
    \repeat 9 {%
        \arcr 0.5 360
        \right 40
    }}
\def\petal #1 {%
    \repeat 2 {%
        \arcr #1 60
        \right 120
    }}
\def\flower #1 {%
    \repeat 6 {%
        \petal #1
        \right 60
    }}
\def\ray #1 {%
    \repeat 2 {%
        \arcl #1 90
        \arcr #1 90
    }}
\def\sun #1 {%
    \repeat 9 {%
        \ray #1
        \right 160
    }}
\vskip 70pt
\turtleline{\circles, \flower 1, \sun 0.3,}

\vskip 70pt
\bigskip
Some poligons
\def\polycommon #1 #2 #3 #4 #5 {%
    \tmpnum=1
    \edef\side{\expr{#1}}%
    \edef\angle{\expr{#2}}%
    \edef\n{\expr[0]{#5}}%
    \def\polyiter {%
        \forward {\side}
        \right {\angle}
        \ifnum\tmpnum<\n
            \advance\tmpnum by1
            \edef\side{\expr{\side + #3}}%
            \edef\angle{\expr{\angle + #4}}%
            \ea\polyiter
        \fi
    }%
    \polyiter
}

\def\poly #1 #2 #3 {\polycommon #1 #2 0 0 #3 }

\vskip 70pt
\turtleline{\poly 50 72 5, \poly 30 60 6, \poly 50 144 5, \poly 70 135 8, \poly 60 108 10,}

\vfill\eject
Outward pirals
\def\polyspi #1 #2 #3 {\polycommon #1 #2 #1 0 #3 }

\vskip 50pt
\turtleline{\polyspi 1.5 95 50, \polyspi 2 90 50, \polyspi 4 120 30, \polyspi 2 117 50,}

\bigskip
\vskip 50pt
Inward spirals
\def\inspi #1 #2 #3 #4 {\polycommon #1 #2 0 #3 #4 }


\vskip 50pt
\turtleline{\inspi 4 0 7 540, \inspi 10 40 30 72, \inspi 10 2 20 90, \inspi 7 1 5 720,}

\bye