Like their fellow SPs, ISTPs are fundamentally Performers (note the capital 'P' :)), but as Ts their areas of interest tend to be mechanical rather than artistic like those of ISFPs, and unlike most ESPs they do not present an impression of constant activity. On the contrary, they lie dormant, saving their energy until a project or an adventure worthy of their time comes along - and then they launch themselves at it. The apparently frenzied state that inevitably ensues is actually much more controlled than it appears--ISTPs always seem to know what they're doing when it comes to physical or mechanical obstacles--but the whole chain of events presents a confusing and paradoxical picture to an outsider.