Convert from cover to shed

Unit Definition (cover)
The Cover is a traditional Welsh unit of area, standardized in the British system to be exactly 2/3 acre (about 0.2698 hectare). The word is an Anglicized version of the Welsh name cyfair for the unit.

Unit Definition (shed)
The shed is an exceptionally small unit of area used in particle physics. Like its big brother, the barn, the shed is used to express the apparent cross-sectional area of a particle from which other particles are scattered. One shed equals 10E-24 barn, which is 10E-52 square meter or 0.0001 square yoctometer.