The overthinking of LLM

I asked Deepseek to draw the Schlegel diagram of a hexahedron — should be a very simple task right? Just 2 squares and link up their vertices. And yet I noticed something interesting: it tends to overthink and end up outputting nonsense answers when DeepThink is on (which is supposed to be more powerful and “clever”), but getting the task done correctly when DeepThink is off. Huh.

So this is the prompt I gave Deepseek:

draw the schlegel diagram of hexahedron with tikz

With DeepThink and Search (accessing internet), it “thought” for >15 minutes and gave me a complete trash:

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}[scale=2]

% Define vertices for the Schlegel diagram
% Outer pentagon (face 1)
\coordinate (A) at (0,2);
\coordinate (B) at (1.9,0.6);
\coordinate (C) at (1.2,-1.6);
\coordinate (D) at (-1.2,-1.6);
\coordinate (E) at (-1.9,0.6);

% Middle ring vertices
\coordinate (F) at (0,1.2);
\coordinate (G) at (1.1,0.9);
\coordinate (H) at (1.4,-0.4);
\coordinate (I) at (0.7,-1.2);
\coordinate (J) at (-0.7,-1.2);
\coordinate (K) at (-1.4,-0.4);
\coordinate (L) at (-1.1,0.9);

% Inner pentagon (central face)
\coordinate (M) at (0,0.4);
\coordinate (N) at (0.6,0.2);
\coordinate (O) at (0.4,-0.5);
\coordinate (P) at (-0.4,-0.5);
\coordinate (Q) at (-0.6,0.2);

% Draw all edges
% Outer pentagon (face 1)
\draw[thick] (A) -- (B) -- (C) -- (D) -- (E) -- cycle;

% Connections from outer to middle ring
\draw[thick] (A) -- (F);
\draw[thick] (A) -- (L);
\draw[thick] (B) -- (F);
\draw[thick] (B) -- (G);
\draw[thick] (C) -- (H);
\draw[thick] (C) -- (I);
\draw[thick] (D) -- (I);
\draw[thick] (D) -- (J);
\draw[thick] (E) -- (J);
\draw[thick] (E) -- (K);

% Middle ring connections
\draw[thick] (F) -- (G) -- (H) -- (I) -- (J) -- (K) -- (L) -- cycle;

% Connections from middle ring to inner pentagon
\draw[thick] (F) -- (M);
\draw[thick] (F) -- (N);
\draw[thick] (G) -- (N);
\draw[thick] (G) -- (O);
\draw[thick] (H) -- (O);
\draw[thick] (H) -- (P);
\draw[thick] (I) -- (P);
\draw[thick] (I) -- (Q);
\draw[thick] (J) -- (Q);
\draw[thick] (J) -- (M);
\draw[thick] (K) -- (M);
\draw[thick] (K) -- (N);
\draw[thick] (L) -- (N);
\draw[thick] (L) -- (Q);

% Inner pentagon (central face)
\draw[thick] (M) -- (N) -- (O) -- (P) -- (Q) -- cycle;

% Draw vertices as small dots
\foreach \point in {A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q}
    \filldraw (\point) circle (1pt);

\end{tikzpicture}

\end{document}

But without Deepthink and Search, it gave me a nice and clean (and correct!) solution:

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}[scale=1.5]

% Define vertices for the cube Schlegel diagram
% Outer square (one face of the cube)
\coordinate (A) at (0,0);
\coordinate (B) at (3,0);
\coordinate (C) at (3,3);
\coordinate (D) at (0,3);

% Inner square (the opposite face projected inside)
\coordinate (E) at (1,1);
\coordinate (F) at (2,1);
\coordinate (G) at (2,2);
\coordinate (H) at (1,2);

% Draw all edges
% Outer face
\draw[thick] (A) -- (B) -- (C) -- (D) -- cycle;

% Inner face (back face)
\draw[thick] (E) -- (F) -- (G) -- (H) -- cycle;

% Connecting edges (the other 4 faces)
\draw[thick] (A) -- (E);
\draw[thick] (B) -- (F);
\draw[thick] (C) -- (G);
\draw[thick] (D) -- (H);

% Additional edges to complete the cube structure
\draw[thick] (A) -- (B);
\draw[thick] (B) -- (C);
\draw[thick] (C) -- (D);
\draw[thick] (D) -- (A);
\draw[thick] (E) -- (F);
\draw[thick] (F) -- (G);
\draw[thick] (G) -- (H);
\draw[thick] (H) -- (E);

% Draw vertices as dots
\foreach \point in {A,B,C,D,E,F,G,H}
    \filldraw (\point) circle (2pt);

% Label vertices
\node[below left] at (A) {1};
\node[below right] at (B) {2};
\node[above right] at (C) {3};
\node[above left] at (D) {4};
\node[below left] at (E) {5};
\node[below right] at (F) {6};
\node[above right] at (G) {7};
\node[above left] at (H) {8};

\end{tikzpicture}

\end{document}

Very weird.