Explanatory notes

OverDrawing
Select on [OverDraw...Choice] one parameter to let it vary, and input values of [Step]
(positive value) and [Times](integer), then click [Draw]. Loci by the [Step] for the 
selected parameter will be drawn. Initial values: Choice a, Step 1, Times 0.

Others
[Interval x=],[to]: Varyinginteval of x. Initial value is -8 to8. If the actual varying
interval is -1 to 1, it will be effective to input so.

[y-axis]: Distance of y-axis from left. Pixels. Left 0, Right 950, Default 470. Change
value if shift of origin is necessary to horizontal direction. 
[x-axis]: Distance of x-axis from top. Pixels. Top 0, Bottom 600, Default 300. Change
value if shift of origin is necessary to vertical direction. 

[Size]: Width of major grid lines. Pixels. Default 50. Scale will be greater by the 
greater value.

[Delay]: Index of slow drawing. Default 0(fastest). Slow drawing will sometimes better
to understand the equations. Input positive integer to draw slowly.

[Precision]: Precision of array of dots to shape the locus. Default 1. 

[Dots/Line]: Drawing modes of locus. [Dots]:Draw by dots. [Line]:Draw by line. 
Default "Line". This is useful to make the locus better.

[System]: Modes of expression of coordinate system. [Full]:Full expression with minor 
grids. [Grid]:Expression by major grids without minor grids. [Axes]:Only coordinate
axes. [None]:No coordinate system shown. Default "Full".

Red marks on the axes: Origin and unit.