# -*- tcl -*- tcl.tk//DSL diagram//EN//1.0

set f [5 cm]
set pi [expr {atan2(0, -1)}]
for {set i 0} {$i <= 2*$pi} {set i [expr {$i + 0.1}]} {
    set k [expr {$f*$i/2.}]
    text text "-" at [$k 0]
    text text "." at [$k [expr {$f*sin($i)/2.}]]
    text text ":" at [$k [expr {$f*cos($i)/2.}]]
}