There's this carpet plant that has recently been dotting the fields here at Rio Grande, I want to know what it is, looks appealing, to me. It's the first time I've seen the flowers of this guys dotting the football field in our school. I'd like to know what they are.

Plant with flower.

These have been around a little longer...

What's this?(Purple flower, the yellow guys have been there since I was born.

There's been a recent addition of a lot of new plants, these are only three.
Why the sudden change?