Mills' Mess variant of the Boston Mess in which every catch from one hand is clawed. Eric's Extension, invented by Eric Uhrhane, is a variation on Mills Mess in which the arms cross twice on each side instead of just once. The extra throws may add to the visual appeal of the pattern. Eric's Extension requires the juggler's arms to be slender or flexible to cross two times, a requirement which makes this variation physically impossible for some. It is especially difficult with clubs. When combined with chops (a "chop" is a downward sweep or flourish of the hand that has just
Constant k filter that. The design techniques used by Campbell have largely been superseded. However, the ladder topology used by Campbell with the constant k is still in use today with implementations of modern filter designs such as the Tchebyscheff filter. Campbell gave constant k designs for low-pass, high-pass and band-pass filters. Band-stop and multiple band filters are also possible. Some of the impedance terms and section terms used in this article are pictured in the diagram below. Image theory defines quantities in terms of an infinite cascade of two-port sections, and in the case of the filters being discussed, an infinite ladder