Wiring plants in sand and gravel is tricky. You can't rely on the earth to hold the wire cage or trellis in place like loamy soil can, so most conventional forms are too top heavy and can sag or topple over. A pyramid is an ideal form for wiring under these conditions. Gravity wind will push it towards the ground, allowing it to quickly settle and become quite stable.
Drill holes through three 2 x 2 boards, approximately five feet in length.
Drive the ends of the boards without holes in them into the sand or gravel so that the points where they intersect the ground form a triangle with sides about two feet in length. Bury the ends at least six inches deep. Wire the exposed ends together to form a tripod.
Plant your plants. If you want them to grow straight up, plant them directly under the tripod. If you want them to grow sideways, plant them off to the side.
Wrap a wire tightly around one of the boards at the point where it meets the ground. Run this wire to the next board and wrap it around, then around the third board and back to the beginning. You have now created a stable pyramid.
Use pliers to twist four lengths of stiff wire tightly around the tripod near the top. You can attach the wires to the point where the boards meet, or bend them around one of the legs of the tripod slightly below the top.
Bend three wires so that they attach to the horizontal wires near the bottom in the middle of the horizontal wire. Extend the fourth one straight down so that it is embedded in the ground.
Train plants beside the wire pyramid to the side wires. Train a plant below it to the vertical wire.