Venn diagram of 4 sets (A, B, C, &amp; D) with all 16 possible areas numbered (0 to 15).  Those 16 numbers correspond to the minterms of Image:K-map minterms.svg used in a 4-variable Karnaugh map.
K-map_4-variable_Venn_with_minterms.svg
derivative work: Moberg (talk)
K-map_4-variable_Venn_with_minterms.svg: en:User:Cburnett