Writing a LayoutStrategy in Bloc can be easy. Generic layout strategies get complex because they can be parametrized a lot. That tends to distract from the essentials. In this case, all I need is a strategy that adds submorphs from left to right in the panel, breaking to a new line when it is full, and recalculate the height when finished. A LayoutStrategy needs to provide only one method #layout:in:. In that, the morph and its submorphs need to be layouted in the proposed bounds. These bounds can be changed. Resizing needs to happen with #innerExtent:, not with #extent: as that results in a non-interruptible loop. Instead of using #submorphsDo, Bloc uses #layoutComponentsDo:. BlCardLayout>>layout: aMorph in: newBounds |offset maxHeight| offset := 0@0. maxHeight := 0. aMorph layoutComponentsDo: [ :component | offset x + component width > newBounds width ifTrue: [ "start a new line" offset := 0@ (offset y + maxHeight). maxHeight := 0]. component position: offset. maxHeight := maxHeight max: component height. offset := (offset x + component width) @ offset y]. maxHeight + offset y > aMorph height ifTrue: [ aMorph innerExtent: aMorph innerExtent x @ (maxHeight+ offset y)] For the card wall I'll need to add margin and inset. Stephan