Freehand system and method for creating, editing, and manipulating block diagrams

A method of integrating freehand user input into a block diagram environment is disclosed. The freehand user input is a user's approximation of a diagram component or feature of a component which is received by the block diagram environment and compared to multiple patterns stored in a storage location. The storage location holds patterns of block diagram components and block diagram component features. The freehand user input may be displayed, superimposed on a block diagram being shown to the user. Upon the freehand user input being matched to one of the patterns representing a block diagram component or feature of a component, the freehand user input is replaced on the displayed block diagram with an electronic device drawn rendering of the matched diagram feature component or feature of a component. Partial matches of the user drawn input may result in a menu of choices being presented to the user for selection.