Plaid models, for microarrays and dna expression

Plaid models were invented by Laura Lazzeroni and Art Owen.
Plaid models describe clusters of genes where:

A gene can belong to more than one cluster
Each gene cluster is defined with respect to some, but not necessarily all, samples
Genes cluster samples, and samples cluster genes, in the same model

Published as:

"Plaid Models for Gene Expression Data", Laura Lazzeroni and Art Owen Statistica Sinica Vol. 12, No. 1, pp. 61-86. January, 2002.
Link to the article at JSTOR
Plaid links at Google scholar

Software

Plaid is now included in the BiClust R package.
It is based on an algorithm from Heather Turner's PhD thesis. Her work is described in this article.