member in some cases it is desirable to have the sheet cover material doubled under before sewing or adhering the cover sheet material to ledge 52 in either arrangement the resulting structure is an attractive seat and or back member referring to fig6 a covered seat member similar to fig5 is shown but with a cushioning pad material 56 extending over the body support area such cushioning material can be adhered or sewed to ledge 52 but preferably as shown in fig6 an ornamental or decorative cover sheet 58 is applied over padding 56 with the cover sheet 58 extending beyond the edges of the padding material and being sewed or adhered to ledge 52 in the same manner as in fig5 this also results in a very attractive seat and back member the purpose of fig7 is to illustrate the fact that an occasional elongated protuberance of a component such as component 20 can have the continuity along its length periodically terminated as long as such periodically terminated protuberances are in the minority and each is contiguous to a continuous protuberance so that there is a small loss of sheet stiffening and spring action in this modification instead of all the elongated protuberances 26 being continuous from margin to margin of the body support area an occasional elongated protuberance is made discontinuous by being severed or discontinued at some point or points 65 along its length such as where in contiguous protuberances there is a direction changing portion at the severance points the severed elongated protuberances terminate at slightly slanting walls 66 similar to walls 36 closing each end of elongated protuberances 26 in the illustrated embodiment the severance points 65 in nearest adjacent discontinuous elongated protuberances are disposed in location.