Abstract: The present teachings provide a hand-holdable body (14) adapted to be freely holdable by a hand of a user; and a trajectory assembly operatively connected with the hand-holdable body, the trajectory assembly including: a shaft (76) extending from the hand-holdable body; a pivot frame (26) coupled with the shaft. The trajectory assembly includes a guide member (20) pivotally connected with the pivot frame; a support member outwardly extending from and connected with the guide member; two actuators coextending and substantially parallel to an axis of the shaft with each actuator pivotally connected with the support member. The trajectory assembly converts linear movement of the actuators into pivotal movement of the guide member to adjust a trajectory axis. The guide member is adjustable to a target trajectory, adjusting the trajectory axis of the guide member in at least two degrees of freedom to align the trajectory axis with the target trajectory.