After all the holes have been made take bamboo skewers and stick them in the hole on the red line and out the hole on the blue line making sure they go straight across.
Next take white glue and glue all the holes so the skewers won't fall out.
When the glue is dry snip off all the parts that are sticking out.
When you look inside the tube it will look like a spiral DNA.
Out of a heavy piece of cardboard cut two circles to cover up each end.
First cover one end and secure with masking tape.
In the other end pour in half to three quarters cup of small aquarium gravel.
Cover and secure that end.