[left] Commercially available extendable poles. (Slipstream/ DEHCR) [middle] Homemade extendable PVC framework. (Slipstream/ DEHCR) [right] A 1¼-inch PVC pipe with a 1-inch PVC pipe inside it allows poles to move up and down and clamp in place. (Bob Pfeiffer, Slipstream/DEHCR)