Requires Ahem font. There are two regions with two ractangle shape-insides, the shape-insides are smaller and have top and left offsets inside the content box. The rectangular shapes boundaries are represented by the blue rectangles. The inline content should flow inside the blue ractangles, the overflow should be pushed down below the last region's content box

Bug 116252 [CSS Regions][CSS Exclusions] shape-inside on regions should respect positioned shapes and overflow