Four Whistles Version 2 is my first attempt at a "calliope" (well, sort of calliope) design utilizing the primitive knowledge I gained from the original Four Whistles model (https://www.youmagine.com/designs/four-whistles). Not being a musician and being "slightly hard at hearing", while it may not sound like it this model is attempting to play "Mary Had A Little Lamb" using a balloon to power the whistles and a hand crank to power a cylindrical sequencer. https://www.youtube.com/watch?v=ar0mMsyuebw https://www.youtube.com/watch?v=NI0hl4TDPpU In order to play "Mary Had A Little Lamb", I incorporated four whistles in the design of this model, each controlled by one of four air valves. Each of the air valves are controlled by a rotating cylinder containing small 2.5mm "bumps" that activate the valves in the correct order (the "cylinder sequencer"). In order to minimize air loss and maximize play time, I designed the valves with a 3 degree preload, designed the valve "axles" using a virtually airtight membrane with torsion bars, and as a last defense against air leaks, used clear silicon caulk to seal the valve body assembly (see below). The caulk is not necessary, but will assist in producing a marked improvement in the models performance. In order to complete this model, you will need to purchase a "punch balloon", one roll of .7mm thick rubber electrical tape (you will only need 3 inches or so, I used Scotch 2242), a bottle of "thick" cyanoacrylate glue and a small tube of clear silicone or acrylic caulk. I also used scissors, a single bevel razor blade, a modeling knife, a needle file set, a small slip joint plier, a jewelers screwdriver set, a rubber mallet and a vise for assembly. And as usual, I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make mistakes in plenty. Designed using Autodesk Fusion 360, sliced using Cura 2.3.1, and printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended.