Base platforms customizable into ICs are designed by identifying a plurality of macros for placement on the platform, each macro being defined in part by a plurality of elements that perform respective functions of the macro. Identical elements in a plurality of macros are identified, and a common element is placed on the platform for an identical element of at least two macros. All other elements of the macros are placed at locations on the platform relative to the common element as to satisfy macro placement rules for each macro. Identical elements can be identified by identifying similar elements in a plurality of macros, and creating a common element generic to the similar elements. The user designs a metalization layer to select macros and configure common elements to the selected macros.