Add initial prototype.

4-high/gel/source/dolly/gel-dolly-simple.ads

@@ -0,0 +1,35 @@
+package gel.Dolly.simple
+--
+--  Provides a simple camera dolly.
+--
+is
+   type Item is new gel.Dolly.item with private;
+   type View is access all Item'Class;
+
+
+   ---------
+   --- Forge
+   --
+
+   overriding
+   procedure define  (Self : in out Item);
+   overriding
+   procedure destroy (Self : in out Item);
+
+
+   --------------
+   --- Operations
+   --
+
+   overriding
+   procedure freshen (Self : in out Item);
+
+
+
+private
+
+   type Direction_Flags is array (Direction) of Boolean;
+
+   type Item is new gel.Dolly.item with null record;
+
+end gel.Dolly.simple;