code: function(csg) {
              var csgs;
              if (csg instanceof Array) {
                  csgs = csg;
              } else {
                  csgs = [csg];
              }
              var result = this;
              for (var i = 0; i < csgs.length; i++) {
                  var islast = (i == (csgs.length - 1));
                  result = result.intersectSub(csgs[i], islast, islast);
              }
              return result;
          }
docs: Return a new CSG solid representing space both this solid and in the solid `csg`. Neither this solid nor the solid `csg` are modified.  A.intersect(B)  +-------+ |       | |   A   | |    +--+----+   =   +--+ +----+--+    |       +--+ |   B   | |       | +-------+