Ruby looks like LISP sometimes

fragment.rb

.map { |subject_answers|
      subject_answers.merge(
        summary: (subject_answers[:summary_r] || subject_answers[:summary_w])
          .keys
          .inject({}) { |memo, material|
            memo.merge(
              material => subject_answers[:summary_r][material]
                .keys
                .inject({}) { |memo, probe|
                  memo.merge(
                    probe => subject_answers[:summary_r][material][probe]
                      .keys
                      .inject({}) { |memo, stat|
                        memo.merge(
                          stat =>
                            (subject_answers[:summary_r][material][probe][stat] rescue 0) +
                            (subject_answers[:summary_w][material][probe][stat] rescue 0)
                        )
                      }
                  )
                }
              )
          }
        )
    }