Problems with using UI-grid tables in angularjs

     var layout = [
            {
                field: "id",
                displayName: "",
                width: 60,
                headerCellClass: "text-center"

            }, 
            {
                field: "zzmc",
                displayName: "",
                headerCellClass: "text-center",
                width: 150
            }, 
            {
                field: "x",
                displayName: "2015",
                width: 400,
                columns: [
                    {    
                        field: "y",
                        displayName: "",
                        width: 100

                    },
                    {
                        field: "z",
                        displayName: "",
                        width: 100

                    }
                        ]

            }
           ]

< H2 > Thank you very much for bothering the veteran for one or two suggestions. < / H2 >