Richard Suchenwirth 2007-06-12 - 'A figure used in many Asian cultures to symbolize the unity of the two "opposite" male and female elements, the "yin" and "yang."' [L1 ] Here's a solution on a canvas with 4 arc items:
package require Tk
proc yinyang {w x0 y0 diameter {col1 black} {col2 white}} {
set xm [expr {$x0 + $diameter/2.}]
set ym [expr {$y0 + $diameter/2.}]
set x1 [expr {$x0 + $diameter}]
set y1 [expr {$y0 + $diameter}]
set y2 [expr {$ym - $diameter/4.}]
set y3 [expr {$ym + $diameter/4.}]
$w create arc $x0 $y0 $x1 $y1 -start 0 -extent 180 -fill $col1
$w create arc $x0 $y0 $x1 $y1 -start 180 -extent 180 -fill $col2
$w create arc $x0 $y2 $xm $y3 -start 0 -extent 180 -fill $col2 -outline $col2
$w create arc $xm $y2 $x1 $y3 -start 180 -extent 180 -fill $col1 -outline $col1
}#-- Test and demo:
pack [canvas .c] yinyang .c 20 20 100 red blue
http://tclerswiki.googlepages.com/yinyang.jpg
