I want to make the effect is like this:
, the effect of the legend of how to set?

I now approach:

 legend: 

{
Received: "vertical",//vertical, horizontal 
X: "10%", 
Bottom: 0, 
Width: "50 px", 
Align: "left", 
Data: [" Load Capacity "and" Heating Operation ", "Boiler Operation area"], 
}, 
{
Received: "vertical", 
X: "35%", 
Bottom: 0, 
Width: "50 px", 
Align: "left", 
Data: [" Unit Maximum Capacity, "" the Unit Capacity Regulation"], 
}, 

Effect of code is like this: