LOGO-L> 3d Moebious strip First time in logo ever

[MHELHEFNY@FRCU.EUN.EG]

;Hello George Mills
;Here is the true 3-d code for the moebious strip using a cylindirical
;co-ordinate system.
;the equation of the moebious band or strip is:
;rho = c + u*cos t/2  , y = t  , theta = c + u*sin t/2
;It is natural to plot the Moebious strip in those co-ordinates.
;N.B. This curve is a poular demo in "Mathematica"&"Maple" packages.
;Best Regards
;Mhelhefny
;-------------------------------------------------------------
to 1turnon3d
; This is a library procedure for 3-d
perspective
setturtle -1  
setxyz -1200 1200 -1200
setturtle 0 cs ht
end

to cylpos :r :fi :y
;this is a library procedure for cylinderical co-ordinates
setxyz :r*cos :fi :y :r*sin :fi
end

to go
1turnon3d setpc [255 0 0]
pu moeb1 50 moeb2 50
end

to moeb1 :a
for [r -:a :a 7][for[fi 0 360 9][cylpos 300+ :r* cos :fi/2 :fi 300+ :r* sin
:fi/2 pd]pu]
end

to moeb2 :a
for [fi 0 360 9][for[r -:a :a 7][cylpos 300+ :r* cos :fi/2 :fi 300+ :r* sin
:fi/2 pd]pu]
end

to turnon3d
; This is a library procedure for 3-d
perspective
setturtle -1
setxyz 1000 1000 1000
setturtle 0 
end
;---------------------------------------------------
Z


dir

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