In first grade we were given a workbook for learning how to write the letters. There was one whole page of A, one page of B, etc. You had to write maybe 100 As in a row. The kids quickly figured out that the fastest way to do it was to first write the left slant 100 times, then the right slant 100 times and finally all the 100 crossbars. So yes, you do need a little variety to defeat such shortcuts.