Microarrays and method for running hybridization reaction for multiple samples on a single microarray

A microarray comprising:

• a microarray substrate comprising a plurality of identical physical detection blocks in repeating units next to each other, each physical detection block comprising an identically arranged complete set of probe-containing features;
• at least one signal for unambiguously identifying a corner of the physical detection blocks, each feature having an ascertainable position relative to the at least one signal;
• and
• physical barriers defining on the substrate at least first and second compartments having a shape and being larger than a physical detection block, each compartment defining a virtual detection block comprising at least one of each probe-containing feature, the features in each compartment being members of at least two sets of features, and comprising the at least one signal, the compartments not being in fluid communication with one another.