A mosaic needs an arm for every count

A shelf of equal cards gives every entry the same size, which throws away the one thing a ranked list is about. A mosaic gives the first entry a tile two to four times the area of the rest — the factor depends on the arm, and at exactly two entries both tiles come out the same size and the mosaic stops encoding rank at all — so the ranking is legible before a number is read. The cost is that a mosaic is a fixed arrangement, and a fixed arrangement has to answer for every input length — which is where the entries go missing.