Clamp a block of timber to bench to help hold pipe steady. Use a fine-toothed saw to cut pipes along line, rotating pipe as you go. Sand cut edges smooth using sandpaper. Repeat with remaining pipes.
Lay pipes out on a bench to create your pattern. Make sure there are 2 of larger pipe diameters at bottom of design. Prime, then apply PVC cement to where pipes touch. Drill 2 holes through both pipes and fix together using pop rivets. As different pipes have different wall thicknesses, you will need to switch between different rivet lengths. Adjoining pieces of larger pipes will be too thick for pop rivets, so screw together using 20mm button head screws, being careful not to overdrive screw.
Dig a 200mm-deep hole for your sculpture to stand. Place sculpture in hole and fill with concrete. Ensure that sculpture is plumb.
Spray paint sculpture in Rust-Oleum Gloss in your selected colour and let dry.