Snoopy is mid-crash here, his doghouse-turned-Sopwith Camel hit and trailing smoke, the World War I Flying Ace spilling backward over the ridge of the roof with goggles up and scarf streaming. This is the moment in It's the Great Pumpkin, Charlie Brown where the fantasy collides with gravity, the Red Baron unseen but very much present, and Snoopy losing altitude exactly as the title says. The doghouse spirals, the smoke curls off to the left, and the whole gag depends on us believing, for one beat, that a dog on a kennel really is a fighter pilot going down over France.

This is "Losing Altitude," a hand-painted limited edition from Peanuts Film Gallery, hand-inked and painted over a studio printed lithographic background, here numbered 292 of 500 and recreated from the original 1966 special. The certificate that accompanies it is signed by Bill Melendez and numbers the edition, and Melendez has signed the cel itself at lower right, where the signature and number now show some fading. He was the only animator Charles Schulz trusted to bring the Peanuts characters to the screen, the man who directed and produced the special and, famously, voiced Snoopy himself by recording his own whines and gibberish and speeding up the playback. A signature from him on a piece of Flying Ace art is about as close to the source of the whole enterprise as the edition gets.

The Flying Ace was Schulz's way of putting his beagle into the Great War without the war, isolation and resilience worked out through imagination on a kennel roof, and this frame catches the moment the daydream goes wrong. It is one of the best-loved beats in a special that earned an Emmy nomination in 1966.

What lifts this lot well beyond the cel is what comes with it: a one-of-one intarsia wood sculpture built directly from the same artwork. Intarsia is a centuries-old craft, wood inlay in which different timbers, chosen for their natural grain and tone, are cut to shape and fitted together to form a picture, a technique that flourished in Renaissance Italy on church panels and choir stalls and survives today as a specialist's art. This piece renders the Losing Altitude image in individually cut sections of wood, each painted, treated, polished and assembled, the doghouse in warm reddish stained timber, Snoopy and his scarf and green flight cap raised in relief, the curl of smoke worked as its own shaped panel, fitted with hanging fixings, measuring approximately 90cm high. As a single bespoke object made from a single edition image, it has no twin anywhere.

Together they are an impressive and unique pairing, the flat hand-painted cel and the dimensional wooden sculpture pulled from the same edition artwork. The edition sold out long ago, the sculpture was only ever made once.