What "medium" means here
The medium run is about building. It leans on lines, squares and corners, with the odd T, L, S or Z, and every round sits two or three moves from the board you are holding. You choose where to build, and the walls only ever shut the long way round. Each round stands alone: play every round in the fewest moves and you land on par.
The shapes are drawn fresh every day, weighted toward the square, corner and line of 3 on this tier. Each round on the par line needs at least as many moves as the round before it, so a run always ramps up.