i have solved with SEO but this slows down the program. i just wonder why they don't connect as they are after SEO.
"you wouldn't form the slab and stair at the same time." not sure but they have the same material along with touching each other, imo they should merge and there should be another fundamental changing in the program other than SEO.
Operating System: Windows 10 64-bit
Processor: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz (8 CPUs), ~2.6GHz
Memory: 16384MB RAM
Card name: Intel(R) HD Graphics 530
Chip type: GeForce GTX 960M