I used opaque watercolor pen for myself.
It becomes the color of the nib that the color of the left is tinged with the color of the above can choose two colors.
It mixes naturally also when the color color below is mixed.
不透明水彩のペンを自分用にいじったものです
上の絵 色が二色選択できるうち左のほうの色味を帯びたペン先の色になります
下の色 色を混ぜるときも自然に混ざる