"Beauty of handmade lies in their imperfections, anything perfect is machine-made"
It works for knit items too and cannot be simpler that this! The good news is that you don't even need a sewing machine!
1: Use your sharp crochet hook and thread; *sc, ch1 to the corner, ch3, sc, (ch1, sc)twice, ch3* repeat, join and cut your thread.
Try to space your sc as evenly as you can. A trick you can use to do this is to mark 1/4" with a marker on your sharp hook, measuring from the tip of the hook and then use that mark as your guide.
2: Switch to worsted weight yarn and 4mm hook; sc in each ch1 sp, 3sc in each corner sp, fasten off yarn.
3: Join yarn with an sc to any middle stitch of the 3sc group, sc in each st across, turn
4: ...continue with your favourite project...!