What is this weed?

[claudine]

A very pretty weed took over my lawn I love it, so I don't want to get rid of it, but I'm very curious what is it. Does anyone of you know its name? It grows really fast.
I'm sorry for the quality of these pictures, they were taken with my phone:

Same plant, different light:

The unknown weed and two daisies:

 

[Silver surfer]

It is one of the weedy Potentilla sp. Cinquefoil.
Possibly Potentilla recta.

 

[claudine]

Thank you for your help, Silver surfer I've just goodled Potentilla and its leaves look exactly like the leaves of my lovely weed. I'm wondering if it will start blooming soon, it would be wonderful