Brendon Hartley's grid penalty on debut looks bad enough on the surface -- the news of it had emerged before he'd completed a lap of the COTA circuit. The limit of four power units is applied to each car, not the driver, which is why Hartley gets the penalty. Initially there was confusion about why Hartley would serve a penalty and this has exposed another very bizarre quirk in F1's regulations. Hartley replaced Pierre Gasly for this weekend, and Gasly replaced Daniil Kvyat for Malaysia and Japan. That means Hartley is technically in the car Kvyat started the season with. Kvyat, meanwhile, is back this weekend and technically in the car Carlos Sainz (now at Renault) started the year in. So, in effect, Hartley is serving a penalty for a change made to Kvyat's original car, while Kvyat doesn't have one in Sainz's old car. Make sense? Didn't think so.

Nate Saunders, F1 Associate Editor

Former Ferrari chief track engineer and driver academy head Luca Baldisserri will be Lance Stroll's race engineer on an interim basis, Williams has confirmed, while the Canadian's regular engineer, James Urwin, is on paternity leave. Baldisserri was head of the Ferrari junior programme when Stroll was a member between 2010 and 2015.

Nate Saunders, F1 Associate Editor

Daniil Kvyat is back in the paddock this weekend. The Russian seemed to be in good spirits and refreshed by his two-race break - even though it was a demotion. Though he didn't watch much of the two races he did miss, he joked that the coverage has at least convinced him he doesn't want to become a journalist any time soon.

Nate Saunders, F1 Associate Editor

Here's a look at Pirelli's ultra-soft tyres for the U.S. Grand Prix weekend. The printing on the sidewall is usually purple on this compound but as part of F1's efforts to raise breast cancer awareness, they've gone pink in Austin.

Laurence Edmondson, F1 Editor