The orientation of the grid, and thus how it expands to fit views pushed to it. e.g. a vertical grid will expand vertically. Default = RBOrientationVertical.
public var orientation RBOrientation { get set }

The number of rows/columns (depending on orientation), for each row set (repeats). i.e. [ 2, 3 ] will have a 2, 3, 2, 3, ... repeating number of dimensions. Default = [ 1 ].
public var dimensions [Int] { get set }

Indicates that after the given row the alternateDimensions property should be used instead must be greater than 1. Default = -1. Set to < 1 to disable this feature.
public var useAlternateDimensionsAfterRowIndex Int { get set }

The alternate dimensions to use once useAlternateDimensionsAfterRowIndex comes into affect. Note if this is nil then the normal dimensions value will continue to be used. Default = [] empty.
public var alternateDimensions [Int] { get set }

The method of sizing child views. Default = RBGridPositionerSizeEvenly.
public var sizing RBGridPositionerSize { get set }