Wikipedia:T engine

A T engine, sometimes called a Tee engine, is a new configuration for internal combustion engines. These first cylinder are horizontally position and the second cylinder are vertically position.

T engines typically have a shorter length than equivalent inline engines, however the trade-off is a larger width. T-twin, and T4 engines are the most even numbered layout for two or four cylinders.

Specific configurations
Configurations of T engines which have reached production are as follows:

T-twin

T4

T8