This paper describes a method and a tool that allows a teacher to interactively explain and construct basic algorithms to novice programmers by direct manipulations of variables, indexes and arrays. The method consists in gradually creating a program with the assistance of a tool that captures the teachers actions on the fly. The system offers possibilities for recording a sequence of actions and replaying them. Moreover it is able to take care of conditional statements, as well as loops and macro operations. The tool generates the corresponding program code. As a result, a complete algorithm can be designed and executed without writing a single line of code.