the blue triangles to them if the children aren' currently visiblethere are no linesbut the blue triangles indicate that the node nevertheless has children if you click on the parent nodeits children and the lines to them will appear by clicking the appropriate nodes you can navigate all over the tree for convenienceall the nodes are numberedstarting with at the root and continuing up to for the node on the far right of the bottom row the numbers are displayed to the upper right of each nodeas shown in figure nodes are numbered whether they exist or notso the numbers on existing nodes probably won' be contiguous figure shows small tree with four nodes in the third row the user has clicked on node so its two childrennumbered and are visible figure selecting the leftmost children if the user clicks on node its children and will appearas shown in figure figure selecting the rightmost children these figures show how to switch among different nodes in the third row by clicking nodes in the second row to switch nodes in the fourth row you'll need to click first on grandparent in the second rowthen on parent in the third row during searches and insertions with the find and ins buttonsthe view will change automatically to show the node currently being pointed to by the red arrow experiments the tree workshop applet offers quick way to learn about trees try inserting items into the tree watch for node splits stop before one is about to happenand figure