The second pyramid is shorter and heavier. Three rungs: 4 up and down planks and a 10-count elbow plank hold, 30 seconds of rest, then 8 planks and another 10-count hold, 30 seconds of rest, then 4 planks and a final 10-count hold. Sixteen reps, three holds, no levels to choose between.
Set it beside Day 10 and the design is obvious. That pyramid had five rungs and eighteen reps of pure movement; this one has three rungs and sixteen, but every rung now ends with your body held motionless on the elbows for ten counts. The reps come off and the tension goes on. The hold is ideal punctuation for this exercise too - you finish the last up and down plank in the elbow position anyway, so the hold costs no setup and simply refuses to let you get up when the reps are done. The eight-rep middle rung is where the day is won or lost.
Keep the transitions the same as they were twelve days ago: hands under shoulders, hips quiet, one arm leading at a time. Go straight into the hold without resetting - that is the point of it. In the hold, elbows under the shoulders, hips in line with the spine, and breathe rather than brace; ten counts is short enough that the temptation is to hold your breath and long enough that you should not.
Fewer reps than last time and considerably more reason to watch the clock.
Make it Harder: Take the middle rung to 10 up and down planks and keep every hold at 10 counts.
Make it Easier: Run the rungs at 2 / 4 / 2 and keep all three holds as written.
