A first memory stores stitch control signals. A second memory stores these signals temporarily and reads them out to enable stitches to be formed. As a pattern is stitched, the first memory is readdressed and stitch control signals are successively written into and read out of the second memory. In one embodiment, the second memory is a RAM--in a second embodiment, the second memory is a shift register. Monostable multivibrators are used to operate the memories.