Fibonacci numbers in Tcl

Example for versions ActiveTcl 8.5, JTcl 2.1.0, Tcl 8.4, Tcl 8.5.7

This example uses iterative definition of Fibonacci numbers. 

set fib1 0
set fib2 1
set s ""
for {set i 0} {$i < 16} {incr i} {
    set fib3 [expr {$fib1 + $fib2}]
    set fib1 $fib2
    set fib2 $fib3
    append s "$fib1, "
}
puts "$s..."