import graph_pi;

size(7cm);
scale(false);

real xmin=-2, xmax=4, ymin=-2, ymax=4;
grid(xmin, xmax, ymin, ymax,
     xStep=1, xstep=.5,
     yStep=1, ystep=.5,
     pTick=.7bp+grey, ptick=grey,
     above=false
     );
draw((xmin,0)--(xmax,0)^^(0,ymin)--(0,ymax), 
      1.5bp+0.8*blue);
labeloij(p=1.8bp+.3*blue,
         arrow=Arrow(HookHead(dir=20),8bp,Fill),
         dot(.5*blue));