Yuyushikiゆゆ式 ; Yuyu Shiki ; Yuyu-Shiki

From MangaHelpers: This 4-koma style manga features three school girls as they hang out and chat. Friendly, clueless Yukari, enthusiastic, childish Yuzuko, and the more level-headed Yui hang out and talk about various subjects, like ketchup and mayonnaise, hands, the sun and more. [tethysdust]