Methods, apparatus, and computer-readable media are described herein related to a user interface (UI) for a head-mountable device (HMD). A computing device, such as an HMD, can display at least a portion of a first linear arrangement of cards. The first linear arrangement can include an ordered plurality of cards that can include an actionable card and a bundle card that can correspond to a group of cards. A moveable selection region can be displayed. A given card can be selected by aligning the selection region with the given card. After selection of a bundle card, the computing device can display a second linear arrangement of cards that includes a portion of the corresponding group of cards. After selection of an actionable card, the computing device can display a third linear arrangement of cards that includes action card(s) selectable to perform action(s) based on the actionable card.