pdngen::specify_grid stdcell {
    name grid
    rails {
        met1 {width 0.48 offset 0}
    }
    straps {
        met4 {width 1.600 pitch 153.600 offset 16.320}
        met5 {width 1.600 pitch 153.180 offset 16.650}
    }
    connect {{met1 met4} {met4 met5}}
}