There is no much complicated obfuscation here, except by creating unnecessary subroutines and using weird names, such as "::" and "sub", and weird-looking names such as "O123" and "l234"... With only method and variable names modifications, I could use the code with use strict; and use warnings; without errors.

The clean version of the code:

#!/usr/bin/perl
use warnings;
use strict;
$|= 1;

# This is usefull and required only on win32 machines
eval{require Win32::Console::ANSI;};

# number of JAPHs per graph
my $counter;

# define the parameters for the graph
my ($u,$v);

# a way to slow the counter decrease, see below
my ($a,$b);

while(1) {
    unless ($counter) {
        # choose a random color
        printf("\e[1;%dm", 30+rand(7));
        # clear the screen
        printf("\e[%d;%dH%s",1,1,"\e[J");

        $u = rand 39/999;
        $v = rand 39/999;

        $counter = 3999;

        $b=qw/19 9 1/[int rand 3];
    };
    
    # print J A P H, on the given position
    printf
      (
       # the ansi code mask
       "\e[%d;%dH%s",
       # X
       11*sin($v*$counter) + 13,
       # Y
       39* cos($u*$counter) + 41,
       # one of the four letters
       qw/J A P H/[$counter%4]
      );

    # here is how $a and $b are used.
    ($a++%$b) or $counter--;
}
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