Statements : All buildings are windows. No toys is building. Some tigers are toys.

Conclusions :
I. Some tigers are buildings.
II. Some windows are tigers.
III. All toys are tigers.
IV. Some windows are toys.

No toy is building. All buildings are windows.

Since the middle term 'buildings' is distributed twice and one premise is negative, the conclusion must be particular negative and should not contain the middle term.

So, it follows that 'Some windows are not toys'.

Some tigers are toys. No toy is building.

Since one premise is particular and the other premise is negative, the conclusion must be particular negative and should not contain the middle term. So, it follows that 'Some tigers are not buildings'.