a series of moves in the generic rule-blind style of notation I used earlier
The move sequences given by Gerd in his comment are B d1–4; B 4–b5 and B d1–5; B 5–g6. He also notes that B d1–h5 is not legal, but B d1–a4 is.
How come the Bishop goes from 5 to g6?
The top corners and the top and left sides are shared between h5 and 5, but the bottom side and corners are different. So 5 behaves as h5 from above (and cannot be occupied at the same time as it), and so is diagonally adjacent to g6.
When the Bishop goes from 5 to g6, is it affected if another piece stands on h5?
5 and h5 cannot be occupied simultaneously, so this situation does not arise. But since both are diagonally adjacent (by the same corner) to g6, it would presumably be fine if they could.
The move sequences given by Gerd in his comment are
B d1–4; B 4–b5andB d1–5; B 5–g6. He also notes thatB d1–h5is not legal, butB d1–a4is.The top corners and the top and left sides are shared between
h5and5, but the bottom side and corners are different. So5behaves ash5from above (and cannot be occupied at the same time as it), and so is diagonally adjacent tog6.5andh5cannot be occupied simultaneously, so this situation does not arise. But since both are diagonally adjacent (by the same corner) tog6, it would presumably be fine if they could.