Historically, computer programs were not effectively protected by copyrights because computer programs were not viewed as a fixed, tangible object: object code was viewed as a utilitarian good produced from source code rather than as a creative work. Due to lack of precedent, this outcome was reached while deciding how to handle copyright of computer programs. The Copyright Office attempted to classify computer programs by drawing an analogy: the blueprints of a bridge and the resulting bridge compared to the source code of a program and the resulting executable object code. This analogy caused the Copyright Office to issue copyright certificates under its "Rule of Doubt".