#A48: Lohkous

 I like how naturally the length constraints lead to regions with interesting flow patterns.

https://puzz.link/p?lohkous/6/4/a12b23b24s

https://puzz.link/p?lohkous/12/12/b1a2d1a23c2a1l12l1w1f12m23e23a12k1a12k12l1a1l12c12a12c12b2c