Hello there; While modeling on the perspective screen, you need to catch an outside perspective on the façade that you will fall in love with. For the side facades, there should be grip from the outside of the building, the same for the upper facade. Close the program to fix the problem in a quick way. When turning it on again, open it by holding down ctrl+shift on the keyboard. Keep holding ctrl+shif until you see the cache cleared warning. Good work.