To create a user interface using ModelValueViewContainer from Coad and Nicola (using the Count class as an example):

• Make your View class a subclass of ModelValueViewContainer
• Create a buildView: method to create the View.
• Use makeDisplayBoxOn:for: to create display box views.
• Use makeButton:on:for: to create buttons.
• Use constraintFrame:corner: to layout the views.
• Use addView:in: to compose the views.
• Be sure to send the changed: message to update text views.