Step 1: Materials
1) 2 Litre Bottles X 2
2) 10' Rope (I used Para Cord (550 Cord as its better kown as) BUT anything works well so long as its synthetic as ropes such as hemp, cotton, etc. will likely rot or mildew easier which weakens the rope and inccreases the chance of your hard work getting washed down the river)
4) A Black Sharpie
6) Something REALLY Pointy
Step 2: Starting The Project
Now your going to punch holes in one of the bottles down where the bottom is. I personally used the little seam like line at the bottom of the bottle as a guide and punched 8 holes perpendicular to each other about 1/4" from the seam. I then cut the bottom off the bottle using the same seam to punch the holes as a guide to cut off the bottom.
NOTE: Heating up the object your using to puch the holes just enough to melt the plastic works wonders and kinda saves a little time.