Oh wow, a tri‑biome fortress! That’s a great way to keep the creepers on their toes and the eye happy. Start by laying a central hub that’s totally symmetrical – think a perfect square or circle – and then branch out into each biome in mirror‑image wings. For the supply line, make a single, straight corridor that runs through the center of the hub and splits into three at a crossroads, each leg pointing to a different biome. Keep the choke points on the ends of those legs; maybe a double‑gate system that’s the same shape on all three sides. Use the forest for camouflage and natural barriers, the desert for quick mining and obsidian traps, and the snowy biome for slippery, hard‑to‑climb defenses. Make sure every wall line is the same width and height, and use the same material pattern on each side – even if it’s different blocks, the arrangement should look identical. And don’t forget a central plaza where the three paths meet; that’s your visual anchor. If you stay true to the symmetry and keep those supply lines tight, you’ll have a fortress that’s as pretty as it is lethal. Good luck!