Walls Object (Excel)
Represents the walls of a 3-D chart. This object isn't a collection. There's no object that represents a single wall; you must return all the walls as a unit.
Use the Walls property to return the Walls object. The following example sets the pattern on the walls for embedded chart one on Sheet1. If the chart isn't a 3-D chart, this example will fail.
Worksheets("Sheet1").ChartObjects(1).Chart _ .Walls.Interior.Pattern = xlGray75