F:\dev>perl fabric.pl
How many fabrics are you using?
2
How wide is fabric 1?
1
To be safe, we'll use a width of -1 for fabric 1.
How many different shapes of fabric 1 is a block made of?
1
What is the width of shape 1?
1
What is the height of shape 1?
2
Shape dimensions:
The dimensions of shape 1 are 1x2
You can get 0 piece(s) of shape 1 per
      1" strip of fabric 1.
You can get 36 1" strips per yard.
You can get 0 of shape 1 per yard of
      -1" of fabric 1.
How many of shape 1 do you need per block?
23
You need 23 per block.
How many blocks are you making?
2
You are making 2 blocks.
You need 46 of shape 1.
Illegal division by zero at fabric.pl line 88, <STDIN> line 7.

F:\dev>

##</code><code>##

#!/usr/bin/perl -w
use strict;

# How many fabrics are you using?

my $number_of_fabrics;

print "How many fabrics are you using? \n";

chomp($number_of_fabrics = <STDIN>);

$number_of_fabrics =~ s/\D//; # only allow number input

## $number_of_fabrics ||= 3;  # assume default quietly

unless($number_of_fabrics and $number_of_fabrics >=3 )
{
    warn "Ahem!!! You must enter a NUMBER >= 3, but that's ok, default is 3";
    $number_of_fabrics = 3;
}
#... more to come ... ;D