This paper presents Loco, a graphical, interactive environment to experiment with code obfuscation and deobfuscation transformations, which can be applied automatically, semi-automatically and by hand. Loco is an extension of the multi-platform visualization tool Lancet, combined with an obfuscation infrastructure in the underlying link-time program rewriter Diablo. By use of Loco, a developer can easily navigate through the control flow graph of a program and do fine-grained obfuscation, test new obfuscation transformations, test the robustness of existing transformations or improve existing transformations.