disclosed are four arrangements for providing tactility on a touch surface keyboard . one approach is to provide tactile feedback mechanisms , such as dots , bars , or other shapes on all or many keys . in another embodiment , an articulating frame may be provided that extends when the surface is being used in a typing mode and retracts when the surface is used in some other mode , e . g ., a pointing mode . the articulating frame may provide key edge ridges that define the boundaries of the key regions or may provide tactile feedback mechanisms within the key regions . the articulating frame may also be configured to cause concave depressions similar to mechanical key caps in the surface . in another embodiment , a rigid , non - articulating frame may be provided beneath the surface . a user will then feel higher resistance when pressing away from the key centers , but will feel a softer resistance at the key center .