The options to grow/shrink a pattern or pattern selection only work with powers of two right now (i.e. doubling/halving the number of rows). At least for growing a pattern, allowing other factors, maybe up to 8 or 9, would be sensible. I would imagine x3 would be the most commonly used one, but if there's a UI for choosing different amounts, we might as well support other amounts that are not possible to achieve by combining x2 and x3 growing.