Green Carpet Moth (Colostygia pectinataria)
The Green Carpet is a member of the Geometridae family. These moth are generally triangular in shape when at rest, hence the link to geometry. It helps with identification to look for family features.
The Green Carpet is flying here in Dorset from late May through to the end of June and then we may get a second brood in the autumn depending on the weather.
It widespread and quite common although not a great visitor to light traps.