private void reflectBtn_Click(object sender, EventArgs e)
{
if (xCheckBox.Checked)
{
_shape.ReflectCenterX();
}
if (yCheckBox.Checked)
{
_shape.ReflectCenterY();
}
if (zCheckBox.Checked)
{
_shape.ReflectCenterZ();
}
ShowChanges();
}