Using MSW Logo

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Basic introduction to using Logo programs
More advanced help
Programming resources

Fractal programs in Logo

Fractal snowflake
von Koch (snowflake) curve
Sierpinski gasket
Cesaro fractal
Broccoli fractal
Forest of trees

Fractal star

to star :a
lt 30
repeat 6[fd :a lt 60 fd :a rt 120]
rt 30
end

to star1 :a
lt 30
repeat 6[star (:a/3) pu fd :a pd lt 60 star (:a/3) pu fd :a pd rt 120]
rt 30
end

to star2 :a
lt 30
repeat 6[star1 (:a/3) pu fd :a pd lt 60 star1 (:a/3) pu fd :a pd rt 120]
rt 30
end

to star3 :a
lt 30
repeat 6[star2 (:a/3) pu fd :a pd lt 60 star2 (:a/3) pu fd :a pd rt 120]
rt 30
end

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Fractal snowflake

to starout :a
star :a rt 180
repeat 6 [star :a/3 pu rt 150 fd :a lt 60 fd :a lt 30 pd]
end

to starout2 :a
star :a rt 180
repeat 6 [star :a/3 starout :a/3 pu lt 30 fd :a lt 60 fd :a lt 30 pd]
end

to starout3 :a
star :a rt 180
repeat 6 [star :a/3 starout :a/3
repeat 6[starout2 :a/9 pu rt 30 fd :a/3 rt 60 fd :a/3 rt 30] pu lt 30 fd :a lt 60 fd :a lt 30 pd]
end

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von Koch (snowflake) curve

to allvonkoch

; draws 6 stages on same screen
cs pu fd 280 lt 90 fd 300 rt 90 pd
vonkoch2 200 0
pu rt 90 fd 250 lt 90 pd
vonkoch2 200 1
pu rt 90 fd 250 lt 90 pd
vonkoch2 200 2
pu bk 300 lt 90 fd 500 rt 90 pd
vonkoch2 200 3
pu rt 90 fd 250 lt 90 pd
vonkoch2 200 4
pu rt 90 fd 250 lt 90 pd
vonkoch2 200 5
ht
end

to vonkoch1

; superimposes 6 stages
cs pu lt 90 fd 200 rt 90 pd
vonkoch2 500 0
vonkoch2 500 1
vonkoch2 500 2
vonkoch2 500 3
vonkoch2 500 4
vonkoch2 500 5
end

to vonkoch2 :x :y

; draws single curve size :x stage :y at current cursor position
repeat 3 [side :x :y rt 120]
end

to vonkoch3

; draws sixth stage
cs pu bk 300 lt 90 fd 200 rt 90 pd
vonkoch2 500 5
end

to side :x :y

if :y = 0 [fd :x stop]
side :x/3 :y-1
lt 60
side :x/3 :y-1
rt 120
side :x/3 :y-1
lt 60
side :x/3 :y-1
end

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Sierpinski gasket

to allgasket

; note - draws 7 stages one after the other
cs gasket 1024 1024
gasket1 1024 512
gasket1 1024 256
gasket1 1024 128
gasket1 1024 64
gasket1 1024 32
gasket1 1024 16
ht
end

to gasket :x :n

;note - clears screen, positions cursor, draws gasket size x, smallest triangle size y
cs pu bk 30 lt 90 fd 200 rt 90 pd
gasket1 :x :n
end

to gasket1 :x :n

; note - draws gasket size x, smallest triangle size y, from current position
if :x < :n [stop]
repeat 3 [gasket1 :x/2 :n fd :x/2 rt 120]
end

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Cesaro fractal

to allcesaro

; notes - draws 4 stages on same screen
cs pu fd 200 rt 90 fd 200 lt 90 pd
cesaro1 150 1
pu lt 90 fd 300 rt 90 pd
cesaro1 150 2
pu bk 200 pd
cesaro1 150 3
pu rt 90 fd 300 lt 90 pd
cesaro1 150 4
ht
end

to cesaro1 :s :n

; notes - draws cesaro size :s stage :n from cursor position
; start cesaro1 350 3 - positions cursor and draws stage3
repeat 4 [spike :s :n lt 90]
end

to singlecesaro :s :n

; notes - positions cursor, draws cesaro size :s stage :n
cs pu bk 250 rt 90 fd 150 lt 90 pd
cesaro1 :s :n
end

to spike :s :n

if :n = 0 [fd :s stop]
spike :s*0.453 :n - 1 lt 84
spike :s*0.453 :n - 1 rt 168
spike :s*0.453 :n - 1 lt 84
spike :s*0.453 :n - 1
end

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Broccoli fractal

to broccoli :x :y

; largest square has side x and smallest square has side y
; for example type broccoli 120 2
cs pu lt 90 fd 50 rt 90 pd
broccoli1 :x :y
ht
end

to broccoli1 :x :y

if :x < :y [stop]
square :x
fd :x lt 45
broccoli1 :x/sqrt(2) :y
pu rt 90 fd :x/sqrt(2) pd
broccoli1 :x/sqrt(2) :y
pu bk :x/sqrt(2) lt 45 pd bk :x
end

to square :x

repeat 4 [fd :x rt 90]
end

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Forest of trees fractal

to forest

cs pu fd 500 pd
sycamore1 150
tree 350 -310 120 20 6
tree 200 -290  80 25 6
tree -320 -280 110 27 7
ht
end

to tree :x :y :u :a :s

; draws tree1 at position (x,y)
pu setpos (list :x :y) pd
tree1 :u :a :s
end

to tree1 :u :a :s

; note - draws tree in current cursor position with size :u, angle :a, stage :s
if :s = 0 [stop]
fd :u rt :a
tree1 :u*(0.5+0.04*random 10) :a :s - 1
lt 2*:a
tree1 :u*(0.5+0.04*random 10) :a :s - 1
rt :a bk :u
end

to sycamore1 :x

cs pu bk 300 pd
sycamore2 :x
end

to sycamore2 :x

if :x < 12 [stop]
fd :x
rt 25 sycamore2 :x*0.7
lt 25 sycamore2 :x*0.6
lt 28 sycamore2 :x*0.7
rt 28 bk :x
end

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