http://d.hatena.ne.jp/kiy0taka/20130222

baroque.groovy

enum Direction { L,U,R,D }

def debug = { directions, button = null ->
    def result = """|3${directions[3]}0
                    |${directions[2]} ${directions[0]}
                    |2${directions[1]}1""".stripMargin()
    if (button != null) result = result.replace("$button", '*')
    result
}

int combinationCount = 0
8.times { combinationCount += 4.power(it+1) }

def result = (0..<combinationCount).findResult { int n ->
    def buttons = [n%4]
    while ((n = (int) n / 4)) {
        buttons << (--n%4)
    }
    def directions = args.collect { Direction.valueOf(it) }
    def history = [debug(directions)]
    buttons.each { btn ->
        directions.eachWithIndex { d, i ->
            directions[i] = i == btn ? d : ++d
        }
        history << debug(directions, btn)
    }
    directions == Direction.values() ? history : null
}

println result?.join('\n----\n')