From the vantage point of the Ruby programmer, the only concrete things are the Ruby statements used to model your desired behaviour. When you're teaching goto

From the vantage point of the Ruby programmer, the only concrete things are the Ruby statements used to model your desired behaviour. When you're teaching goto/jumps you'd have to either teach another programming language (raw instructions) which would make it more concrete, but would also raise a lot more questions about how Ruby works, or teach goto in terms of Ruby code, which would make it fairly abstract :P