The twin bees shuttle (or B-heptomino shuttle) was found by Bill Gosper in 1971. Before the Snark was discovered, it and its variants were the basis of all known period46oscillators (the version at right being the smallest based on its minimum population of 28 cells), and until the discovery of Tanner's p46, the basis of all known true period 46 guns including the second known basic gun, new gun 1. The simplest such gun is the bi-gun, in which two twin bees shuttles collide with each other head-on (much like the collision of two queen bees in the Gosper glider gun).
There are numerous ways to stabilize the ends, two of which are shown to the right; a stabilization by two blocks on one end and one block on the other end. This 3-block stabilization produces the smallest possible shuttle in terms of its minimum population. This latter method produces a very large spark which is useful in a number of ways. For example, the large spark can be used to convert an incoming glider into a lightweight spaceship, as illustrated by double X. The image below shows David Bell's double block reaction (on the left), which results in a shorter but wider shuttle than usual, as well as Heinrich Koenig's hat stabilization (on the right). The two-block shuttle, however, has a cheaper glider synthesis, costing only 7gliders instead of 8.
Interactions based on the twin bees shuttle are numerous and can have many applications. Some notable reactions are period 46 oscillators that can directly reflect gliders, lightweight spaceships, and middleweight spaceships, as well as convert gliders to lightweight spaceships and lightweight spaceships to middleweight spaceships.
The period-92 do-see-do reaction was found by David Bell in 1996. It is a 90 degree glider reflection reaction in which the gliders appear to circle around each other.