Straight stitch is probably the most basic embroidery stitch there is. But it evolves into a number of other stitches depending on how many times you stitch over the original and how you format a group of them.
Straight stitch (single satin stitch, isolated satin stitch, seed stitch, spoke stitch, stroke stitch): To make a straight stitch, simply bring your needle up through the fabric and then take it down again a little way away. I’ve used three strands of DMC cotton thread here.
Dot stitch (double seed stitch, double back stitch): To turn a straight stitch into a dot stitch, make another stitch over the first by bringing your needle up and taking it down again through the same holes.
Granitos: Turn a dot stitch into a granitos stitch by making another one or two stitches over the first two. Vary the number of stitches to change the look of your granitos.
Beetle stitch: Make five or six stitches through the same two holes using all six strands of your thread to create a beetle stitch. Allow your thread to fall above or below the needle naturally. The end result is a deliciously fat ball of thread sitting on top of the fabric.
Single seeding (speckling stitch, isolated back stitches, matting) is when you scatter straight stitches randomly, usually to fill a section of a design. You see this a lot in Jacobean embroidery.
Double seeding (speckling stitch, dot stitches, matting) is the same principle as single seeding, just using dot stitches. It’s a bolder filling stitch that stands out more.