```articulation tree
parts:
(1) part_name: base;
(2) part_name: drawer;
(3) part_name: keyboard tray;

links:
(1) link_name: base;
(2) link_name: drawer;
(3) link_name: keyboard tray;

joints:
(1) joint_name: drawer_base_joint; joint_type: prismatic; parent_link: base; child_link: drawer;
(2) joint_name: keyboard_tray_base_joint; joint_type: prismatic; parent_link: base; child_link: keyboard tray;
```