It is hardly surprising that there should be a certain homogeneity in Foster and Partners' drawing style. Commentators and colleagues have, after all, long admired Sir Norman's own exquisite draughtsmanship. Now there are worries that former employees of the firm may be confused with current staff because of their drawing style. Astragal hears Foster staff now have contracts confirming they will change their style when they leave. that's what I call brand management.