A non-toxic mattress and method of constructing the mattress having a reduced toxicity has an outer layer of a material selected from the group comprising polyethylene and polylactic acid film. An oblique averaging part averages pixels obliquely located with respect to the interpolated pixel on the basis of an oblique edge angle signal, and outputs the result of calculation as an oblique average. The sawing controller includes a handle. ABBs will advertise I-SIDs that are common to the L1 and L2 networks back into their respective L1 network.