A default label is generated for each instance of a block. If only one instance of a particular block appears in a model, the block name is used as the default label. Otherwise, an integer is appended to the default label to indicate how many instances of the block have previously been created in the model. The block label is used to identify individual blocks in any lists or dialogs. The label can be displayed next to the block icon in the Model window, but by default, a block label is not visible.