Scot Ellison's search for a smaller p5 oscillator to support the 73-step Herschel conduit was successful, back in May of last year -- though he says that even smaller, perhaps asymmetrical, sparkers are likely to exist.
This smaller p5 fountain is included in an
updated version of Hersrch, Karel Suhajda's Herschel-track search and construction program.
Another p5 Herschel conduit that showed up in 2007 was an adjustable diagonal track in which two gliders to travel an arbitrary distance diagonally between a transmitter and a receiver, similar to Paul Callahan's stable "tandem glider" circuits. It's constructed from known pieces: a stable converter that produces two gliders on the same lane from an input Herschel, and a p5 "doubler" that produces one output glider and/or Herschel from each pair of input gliders.
The circuit's p5 limitation is somewhat mitigated by its reversibility -- there are two mirror-image ways to receive the two gliders, whereas most tandem gliders need either a left- or right-handed receiver. (Some pairs of gliders with two-cell separation, usually produced with the assistance of a boojum reflector, can be received ambidextrously by standard receivers -- but this significantly alters the timing of the circuit.)
Depending on the position of the block, either of the two gliders can be chosen to trigger the Herschel output, while the other one resets the circuit. The circuit can also be hooked up to any glider output of a Herschel track for use as a period doubling fanout device, or a two-state track switch (two circuits on two glider outputs with alternating block positions).
