Mapping the Baseboard

I kept both mittens pressed flat against the skirting board, shuffling sideways one careful inch at a time. The carpet was scratchy, but—wait, my foot bumped something flat and rigid. A clear acrylic drafting ruler was lying right beside the heavy oak desk leg, covered in neat, tiny red grid marks. Perfect right angles. Predictable millimeter dashes! I dropped to my knees, exhaling a quick, shaky breath, and pulled the ruler closer until it aligned flush against the wall. That makes this corner exactly twelve centimeters deep, with a straight line of sight back toward the open room. If I can measure the perimeter... it’s not really chaotic, is it?