anchor.diff:  			data[i].value = nest
   		}
   
  +		// edit options
  +		let opts = {
  +			xTickFormat: (d, i, arr) => ((arr.length + i) % 3) ? null : d3.timeFormat("%b %y")(d)
  +		}
  +
   	  $(".punchcard").each((i, container) => {
  -	    punchcard(`#${container.id}`, data)
  +	    punchcard(`#${container.id}`, data, opts)
   	  })
   	});
   </script>
  
positive.code: 	    bottom: gutter * 1.5,
  	    left: gutter
  	  }
  
  		// dimensions
  		let container = d3.select(context)
  
negative.code: 	    bottom: gutter * 1.5,
  	    left: gutter * 15
  	  }
  		let xTickFormat = options.xTickFormat || (d => d)
  		let yTickFormat = options.yTickFormat || (d => d)
  
  	  // dimensions
  	  let container = d3.select(context)
  