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the main and reserve on the back became known as a “piggyback,” and the introduction of a two-person parachute system became the new “tandem.” [Figure 2-8 and  2-9] 

## Configuration 

When canopies were packed into early bag-type containers, they always wanted to assume a spherical or round shape. For the container to remain flat, it was necessary to tailor the fabric and then use frames or bow stiffeners to keep it flat and compress the pilot chute. Back designs utilized multiple cones and pins, usually three or four to maintain the length and width. Seat containers were usually more square and thicker since they were held in place by the seat pan. Most use two cones and pins for closing. The same was used for chest and lap parachutes. Many military systems still utilize these basic configurations today. 

With the introduction of skydiving in the 1960s, most equipment was of modified military designs, and the first generation of commercial products was simply colored versions of these designs. In the 1970s, skydiving canopies had progressed to ram-air designs, which were smaller in volume and had different deployment requirements. Container designs evolved to meet these requirements. The introduction of the hand deploy pilot chute was probably the 

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