Top-ology

Sometimes you might want to take off the clothes you're wearing underneath the ones you've got on top, like for instance a bra under a blouse but a more substantial garment. Currently, this is not very practical because of the topology of the clothes underneath. What is actually needed is a way to unfasten the clothes so that they become either single topological toroids or a collection of them, and at the same time can be converted to them without having to delve inside one's overgarments. There are various ways of doing this:
1. A sleeved top can consist of two completely separate left and right halves fastened together by laces at the top and bottom of the front and back of the garment. Another possibility is to tie the halves together with strings that pass through hems at the top and bottom of the garment which can be opened out completely to adjust the string when not being worn. The halves of the undergarment could then be removed through the sleeves of what one is wearing on top.
2. A similar arrangement but split at the sides from the bottom along the underside of the sleeves, with fastenings at the bottom of the sleeves and the bottom of the left and right side.
3. Split from the neck to the bottom of the sleeves again, allowing the item to be slid down over the legs, either to be removed completely or to become a skirt.
4. Sleeveless with shoulder straps that can be unfastened and again the garment can either be taken off or worn as a skirt. Something similar to this might already exist.
5. Something that only covers the midriff but can be loosened with drawstrings and removed downwards.