1. A method of configuring a foam spring mattress, comprising: assigning a relevance rating to a foam spring location in the mattress, wherein the relevance rating relates to the relevance of the location of the impact it has on the firmness feel of the mattress; and configuring a plurality of foam springs of varied firmnesses in a mattress according to a placement pattern to obtain a firmness, wherein the placement pattern is generated based on a match between a foam spring of a particular firmness and the relevance rating.