@@vitoria.g.fernandes i dunno if this is helpful now, but you place the 2x1 wall first, then select the 1x1 area you're going to put the wall, but dont put it down yet, undo the 2x1 wall with the keybind {ctrl+z} and place the 1x1 wall and then redo the 2x1 wall with the keybind {ctrl+y}, it should turn out fine if you time it just right {although, I tried doing this on a wall longer than 1 and it didnt work, hope this helps someone}
