What is a Generalizing Specialist (T-Shaped)?
A generalizing specialist — the T-shaped person — has deep expertise in one discipline (the T's stem) plus working competence across several others (the bar). Teams of them flow: when testing backs up, developers test; when design is the bottleneck, others prototype. Teams of pure specialists queue.
It's a team-design goal, not a hiring unicorn: pairing, rotation, and mob sessions grow the bar on people who already have the stem.
Worked example
Sprint crunch: the team's only tester is drowning while two developers wait for "their" work. On a T-shaped team, both developers pick up test automation for two days — slower than the specialist, fast enough to un-jam the sprint. The board flows again. The all-specialist team next door ships three days later, having "stayed efficient" individually and slow collectively.