isSlotRectCoveredByGateInSameColumn(col, row, height) {
        for (let j = 0; j < height; j++) {
            let f = this.findGateCoveringSlot(col, row+j);
            if (f !== undefined && f.col === col) {
                return true;
            }
        }
        return false;
    }
@param {!int} col
@param {!int} row
@param {!int} height
@returns {!boolean}