My question is to what exactly 縦に半回転する means.
For examples sake lets imagine a plane flying in the sky, and how I think its orientation would change.
We will start of with the example that the plane is flying parallel to the ground and maintaining the same height. If it was to 縦に半回転する then it would be flying upside down (180 degree rotation), I think.
Now what if instead maintaining the same height, it was moving upwards at a 45 degree angle from vertically up. If this was to 縦に半回転する would it now be going downwards at a 45 degree angle from vertically down, or would it be going in the opposite direction (horizontally) compared to before?