The term freeze and melt is also used in the Eiffel programming system to express a different concept -- a engineering concept -- the written code can be melted into edit mode for modification and then frozen to running mode by compilation for testing. This requires a frequent edit-freeze-test-melt-modify cycle which is equivalent to the edit-compile-test-modify cycle. The term freeze/melt used here is a language concept: a static type can be melted into dynamic type for redesign and a dynamic type can be frozen into static type for product deployment. Frequent edit-freeze-test-melt-modify cycles are not required in a development phase. Modification and test can be conducted simultaneously in a dynamic programming environment.