If something is awesome, but like totally awesome and rad you can say: thats heller-awesome to let people know it is more than just awesome. Or if something really really sucks heller can be applied also.
That show is heller-awesome. That tshirt is heller-rad. That grind was heller-sweet. That was heller-shit.
Strips of newer, smoother concrete on a pavement that has undergone reconstruction at some point. Usually a seam runs along the pavement and is a different colour or type on concrete. Usually seen on UK pavements.
The seam is smoother than the pavement, lets skate on that for more comfort. The pavement sucks but seam is smooth.