Check out this amazng teacher aide and artist's website. She creates these incredible colouring sheets, alphabets and more, and you can either print and colour them by hand, or use a program like paint to colour them on the computer
Official Zentangle Pattern Draw small squares in a section. Draw squares in evenly spaced rows. Connect the squares with lines - one left, one right, etc. Connect the squares in the other direction to make the warp and weft pattern.