Chapter 20.670 THE HEIGHTS (HX) PLAN DISTRICT Revised This chapter is included in your selections. Sections: 20.670.010 Purpose. 20.670.020 Applicability. 20.670.030 Regulation of Uses. Revised 20.670.040 Design and Development Standards. Revised 20.670.050 Design Standards Modification. 20.670.060 Approval Process.