如图,在平面直角坐标系中,点\(A_{1}\)的坐标为\((1,2)\),以点\(O\)为圆心,以\(OA_{1}\)长为半径画弧,交直线\(y= \dfrac {1}{2}x\)于点\(B_{1}.\)过\(B_{1}\)点作\(B_{1}A_{2}/\!/y\)轴,交直线\(y=2x\)于点\(A_{2}\),以\(O\)为圆心,以\(OA_{2}\)长为半径画弧,交直线\(y= \dfrac {1}{2}x\)于点\(B_{2}\);过点\(B_{2}\)作\(B_{2}A_{3}/\!/y\)轴,交直线\(y=2x\)于点\(A_{3}\),以点\(O\)为圆心,以\(OA_{3}\)长为半径画弧,交直线\(y= \dfrac {1}{2}x\)于点\(B_{3}\);过\(B_{3}\)点作\(B_{3}A_{4}/\!/y\)轴,交直线\(y=2x\)于点\(A_{4}\),以点\(O\)为圆心,以\(OA_{4}\)长为半径画弧,交直线\(y= \dfrac {1}{2}x\)于点\(B_{4}\),\(…\)按照如此规律进行下去,点\(B_{2018}\)的坐标为 ______ .