Chain 150.

Row 1: Skip first ch, sl st into next ch, hdc into next ch, sl st into next ch; rep from to end, ch1, turn.

Row 2: Skip ch, sl st into next st (sl st if previous row), hdc into next st (hdc of previous row), rep from ending with sl st into tch, turn.

Repeat row 2 until you have reached XX length.