Cis decalin
2 fused 6 membered rings, one veritcal. 1 H up, one coming out at 10 o clock (both in middle)
trans-decalin
2 fused 6 membered rings side by side, 1 H up, one down (both in middle)
Bicyclo [2.2.1] heptane (norbornane)
Upside down book with triangle