set O {1 7 16 25 34 43 46 40 31 22 13 4}
set C {8 o \n 4 o {} 7 o \n 0 {} \n 1 o {} 13 o \n 0 {} \n 0 o {} 15 o \n 0 {} \n 1 o {} 13 o \n 0 {} \n 4 o {} 7 o \n 8 o \n}
foreach t $argv {
    if {[regexp {0?(\d+):0?(\d+)} $t -> h m]} {
	set h [lindex $O [expr {($h%12)}]]
	set m [lindex $O [expr {($m/5)}]]
	if {$m==$h} { 
	    set c [lreplace $C $m $m x] 
	} else {
	    set c [lreplace $C $h $h h]
	    set c [lreplace $c $m $m m]
	}
	foreach {s o b} $c { puts -nonewline [string repeat " " $s]$o$b }
    }
}

% tclsh w.tcl 21:35
	o
    o       o

 o	     o

h	       o

 o	     o

    m       o
	o

set tcl_interactive 1
set O {1 7 16 25 34 43 46 40 31 22 13 4}
set C {8 o \n 4 o {} 7 o \n 0 {} \n 1 o {} 13 o \n 0 {} \n 0 o {} 15 o \n 0 {} \n 1 o {} 13 o \n 0 {} \n 4 o {} 7 o \n 8 o \n}
sc [ge stdin] %d:%d h m
set h [lind $O [exp $h%12]]
set m [lind $O [exp $m/5]]
fore {s o b} [if $m==$h {lrepl $C $m $m x} {lrepl [lrepl $C $h $h h] $m $m m}] {pu -nonewline [st repe \  $s]$o$b}