"The basis for all my designs is this 'simple' knitted square"

My squares are all knit 'on the diagonal' more often than not just in a basic garter stitch (all knit rows).

To make a square -
Cast on two stitches. Knit into the front, and back, of the first stitch only in every row until you have reached the required number of stitches according to the pattern you are following.  Then decrease by knitting the first stitch, then knitting the next two stitches together in every row until two stitches remain.  Loop the first of the two remaining stitches over the last one, break off the yarn and thread the end through the last stitch pulling tight to 'bind off'.  Gently pull the square into shape - and there you have it - your first completed square!