Photo #3 shows I used my thumb to push the lace through the 1st loop to create a 2nd loop. You cannot see the 1st loop because my thumb is in it. I take my thumb out of the 1st loop and yank the 2nd loop side to side to tighten the half slipknot.
Dutton, R. (2013) My Last Degree: A Therapist Goes Home After a Stroke, 2nd ed., pp. 90-95. Bangor, Maine: Booklocker.