A tool for creating mechanical stamps that produce machine-readable optical labels. The tool selects an initial element of a list of two-dimensional labels. The tool selects a pixel difference to apply to a two-dimensional label for the initial element. The tool selects a cardinality for bits in one or more bytes to encode. The tool determines whether a cardinality of a bit difference for each element compared to the initial element equals the selected bit difference cardinality. The tool determines whether a pixel difference between a two-dimensional label for each element and the two-dimensional label for the initial element equals the selected pixel difference. The tool selects one or more elements from the list of two-dimensional labels to create one or more mechanical stamps.