Step by step: The bishop can change his diagonal. That's the point of this variant. From b5 to b3 or from g4 to g6 (and so on up/down the diagonal) means that the bishop has changed his diagonal.
When you said step by step, I was expecting a step by step explanation, but you didn't provide one. Could a Bishop move from d1 to e8 along the path d1-c2-b3-a4/4-b5-c6-d7-e8?
When you said step by step, I was expecting a step by step explanation, but you didn't provide one. Could a Bishop move from d1 to e8 along the path d1-c2-b3-a4/4-b5-c6-d7-e8?