Half-bakery is a still life that is made up of two loaves (and makes up half of a bakery). When the term bi-loaf is used, this pattern is its most common meaning.
There is a remarkable reaction where a glider collides with the bi-loaf, displacing it by (3,6) and generating another glider in the same direction as the incident glider. The only other known reactions of this type involve stable reflectors, which have a displacement of (0,0), alongside a constellation of three blocks. This displacement reaction has enabled the construction of half-baked knightships, since there is a way to produce an extra glider using two of them:
It can also act as a one-time glider reflector in various other collisions.
Half-bakery is the eleventh most common still life in Achim Flammenkamp's census, being less common than barge but more common than mango. It is also the fifteenth most common object on Adam P. Goucher's Catagolue.