Make a roach the length and diameter of a thick pencil and seal it with papers or tape.
Cut two large, circular holes either side of the roach, about 3cm from the end.
Make a second roach, half the length of the first and slightly narrower.
Cut the biggest posible hole you can make through the centre of the second roach.
Join the two roaches by inserting the second tube through the hole you made in the first. Rotate the smaller tube untill the central smoke hole is in line with the larger tube. If you can see through all the tubes then you've cracke d it.
Carefully seal the roahes with tape or gummed strips. Keep bandaging untill your sure it's airtight.
To use the roach simply add your choice of joints to the protruding ends. Any joints will work altough it helps if they burn at the same rate.