diff --git a/README.md b/README.md
index 5b8befa..f93285a 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ This library is a customizable 2D math rendering tool for calculators. It can be
 \frac{x_7}{\left\{\frac{\frac{2}{3}}{27}\right\}^2}
 ```
 
-![Sample on a Graph 35+E II](https://framapic.org/CkFr4ab3FjcZ/bXQg9LyozGqg.jpg)
+![Sample image](https://framapic.org/v4ODO95ftSAV/szXvX2amwuUN.png)
 
 ## Features
 
diff --git a/TODO.md b/TODO.md
index c140820..3b7c9a6 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,11 +1,11 @@
-*  Support angle brackets, and honor TEX_LEFTRIGHT_MAX_ANGLE
 *  Write real error messages
 *  Support Unicode symbols (probably requires help from the font side, urgh)
 *  Don't use TEX_LAYOUT_SPACING for everything, just make it the default
 *  Add a parameter to resolve as inline style or display style
 *  Support character-level spacing
+*  Be more generic in what nodes have display mode by default
 
-*  Add sum and products
+*  Add products
 *  Add square roots, and honor TEX_SQRT_SLANTED and TEX_SQRT_BAR_LENGTH
 *  Add vectors
 *  Add limits
diff --git a/src/classes.c b/src/classes.c
index 05f527d..fd9af50 100644
--- a/src/classes.c
+++ b/src/classes.c
@@ -234,6 +234,34 @@ void supsubscript_render(struct TeX_Node const * node, int x, int y,
 	render_flow(args[0], x, y, color);
 }
 
+//---
+//	Summation symbols.
+//	* args: 0 (ignored)
+//	* flow: default
+//
+//	Summation symbols are just nodes with a constant size and function.
+//	They are automatically placed in display mode except if the user asked
+//	for inline mode.
+//---
+
+void sum_size(struct TeX_Node *node)
+{
+	node->width = 9;
+	node->height = 9;
+	node->line = 4;
+}
+
+void sum_render(__attribute__((unused)) struct TeX_Node const * node, int x,
+	int y, int color)
+{
+	TeX_line(x, y, x + 8, y, color);
+	TeX_line(x, y, x + 4, y + 4, color);
+	TeX_line(x, y + 8, x + 4, y + 4, color);
+	TeX_line(x, y + 8, x + 8, y + 8, color);
+	TeX_pixel(x + 8, y + 1, color);
+	TeX_pixel(x + 8, y + 7, color);
+}
+
 //---
 //	The class table and lookup functions
 //---
@@ -249,6 +277,8 @@ struct TeX_Class TeX_table[] = {
 	/* Superscripts and subscripts */
 	{ "\\sup", supsubscript_size, supsubscript_render },
 	{ "\\sub", supsubscript_size, supsubscript_render },
+	/* Sum symbol */
+	{ "sum", sum_size, sum_render },
 	/* Integral */
 	{ "int",     NULL,                   NULL          },
 	/* NULL terminator */
diff --git a/src/flow.c b/src/flow.c
index c954e14..dfab93a 100644
--- a/src/flow.c
+++ b/src/flow.c
@@ -135,8 +135,43 @@ void chunk_compute_inline(struct chunk *chunk)
 /* chunk_compute_display(): Compute chunk layout for display mode */
 void chunk_compute_display(struct chunk *chunk)
 {
-	/* TODO: Display mode for exponents and subscripts */
-	chunk_compute_inline(chunk);
+	struct TeX_Node *base = chunk->base;
+	struct TeX_Node *sup = chunk->sup;
+	struct TeX_Node *sub = chunk->sub;
+
+	int spacing = TEX_LAYOUT_SPACING;
+
+	/* Chunk width and height */
+	chunk->width = base->width;
+	chunk->height = base->height;
+	chunk->line = base->line;
+
+	if(sub)
+	{
+		chunk->width = max(chunk->width, sub->width);
+		chunk->height += sub->height + spacing;
+	}
+	if(sup)
+	{
+		chunk->width = max(chunk->width, sup->width);
+		chunk->height += sup->height + spacing;
+		chunk->line += sup->height + spacing;
+	}
+
+	/* Now that the dimensions are clear, compute the position */
+
+	if(sub)
+	{
+		sub->l += sub->line + (base->height - base->line) + spacing;
+		sub->x = base->x + ((chunk->width - sub->width) >> 1);
+	}
+	if(sup)
+	{
+		sup->l -= (sup->height - sup->line) + base->line + spacing;
+		sup->x = base->x + ((chunk->width - sup->width) >> 1);
+	}
+
+	base->x += (chunk->width - base->width) >> 1;
 }
 
 /* chunk_compute_slanted(): Compute chunk layout for slanted mode */
@@ -285,8 +320,14 @@ void size_flow(struct TeX_Flow *flow)
 		/* Leave the last chunk and make a new one */
 		update(&c, &x, &above, &below);
 
+		int mode = TEX_CHUNK_INLINE;
+		if(!strcmp(class, "sum"))
+		{
+			mode = TEX_CHUNK_DISPLAY;
+		}
+
 		node->x = x;
-		chunk_make(&c, node, TEX_CHUNK_INLINE);
+		chunk_make(&c, node, mode);
 	}
 
 	/* Finish the last chunk */
diff --git a/src/platform/sdl2.c b/src/platform/sdl2.c
index 85e86a6..c521565 100644
--- a/src/platform/sdl2.c
+++ b/src/platform/sdl2.c
@@ -161,9 +161,9 @@ static void fini(void)
 int main(void)
 {
 	char const * formula =
-	"\\frac{x_7\\left<X,Y\\right>+3\\left<\\frac{A}{B}\\right>}{"
+	"\\frac{x_7}{"//\\left<X,Y\\right>+3\\left<\\frac{A}{B}\\right>}{"
 		"\\left\\{\\frac{\\frac{2}{3}}{27}\\right\\}^2"
-	"}";
+	"} + \\sum_{k=1}^nk";
 
 	struct TeX_Flow *flow = TeX_parse(formula);
 	if(!flow) { puts("parsing error!"); return 1; }