This is an entry for Fortnightly Topic Challenge #44: Introduce a new grid deduction genre to the community.
I'm pleased to introduce you to the Dosun-Fuwari puzzle. Rules to fill the grid (translated from an Italian magazine):
- place some anvils (A) and some balloons (B) into the grid. In each region there is exactly one anvil and exactly one balloon (the regions are are outlined with a strong border).
- since balloons are light, they float. Balloons can be placed only in the top row of the grid, under a brick (shaded cell) or under another balloon.
- since anvils are heavy, they fall down. Anvils can be placed only in the bottom row of the grid, over a brick (shaded cell) or over another anvil.
Here is an example easy grid and its solution taken from the same magazine.
Now solve this big grid: