asymptote を使って描いては見たものの、これだけだと何がなんだか解らんし文章を打ち込むのは大変だし、やっぱり手書きノート最強だな。

size(120mm, 80mm);
real margin=1mm;

string s1 = "要請2.1\\ 等温環境での平衡状態";
object block1 = draw(minipage(s1, 120pt), roundbox, (0,0), margin);

string s2 = "要請2.2\\ 環境と温度";
object block2 = draw(minipage(s2, 120pt), roundbox, (2,0), margin);

string s3 = "結果2.3\\ 平衡状態の記述";
object block3 = draw(minipage(s3, 120pt), roundbox, (1,-1), margin);

string s4 = "要請3.1\\ Kelvinの原理";
object block4 = draw(minipage(s4, 120pt), roundbox, (0,-2), margin);

string s5 = "結果3.2\\ 等温準静サイクルの行う仕事";
object block5 = draw(minipage(s5, 150pt), roundbox, (2,-2), margin);

add(new void(frame f, transform t) {
    draw(f, point(block1, S, t){S}..point(block3, N, t){S}, Arrow);
    draw(f, point(block2, S, t){S}..point(block3, N, t){S}, Arrow);

    draw(f, point(block4, E, t){E}..point(block5, W, t){E}, Arrow);
});

$ asy flow.asy
$ convert -geometry 480x320 -density 288x288 flow.eps flow.png