I have created few crossword tables. I find there is no distinguishing between unused cell & used cell unlike we find in conventional crossword puzzles, which appear in black & white. Is there any option I am missing here? If not, it is suggested to add this. Also I noticed repeat of the numbers. That is numbers are split for ACROSS & DOWN. There should not be such repeat of numbers and it should apear only once for ACROSS & DOWN questions. (If look at the attachment, 1 and 2 are repeatedly appearing)

If look at the attachment, the questions generated ACROSS & DOWN are very few out of total 20 questions!? That is only 8x8 portion is used. If any, minimum number of questions required to get full (15x15) crossword puzzle?