write basic scatter circle

d3.max(data, function(d){ return d.x})
axis create: d3.svg.axis().scale().orient()

axis call: svg.append("g").attr().call()

1. trick
        transform: "translate("+ [x, y] +")"

2. translate is used to move element from one position to another
tick si the little vertical line on the axis

we can set tickSize and tickValue