diff --git a/img/lectures/list_evolution.dio b/img/labs/list_evolution.dio
similarity index 84%
rename from img/lectures/list_evolution.dio
rename to img/labs/list_evolution.dio
index 6a6e4d8..1f79255 100644
--- a/img/lectures/list_evolution.dio
+++ b/img/labs/list_evolution.dio
@@ -1,6 +1,6 @@
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@@ -239,57 +239,57 @@
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                 </mxCell>
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                 </mxCell>
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+                <mxCell id="72" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" parent="1" vertex="1">
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                 </mxCell>
-                <mxCell id="119" value="next" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="119" value="next" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
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                 </mxCell>
-                <mxCell id="120" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="120" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
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                 </mxCell>
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+                <mxCell id="122" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;entryX=0;entryY=0.5;entryDx=0;entryDy=0;fontColor=#000000;" parent="1" source="123" target="131" edge="1">
                     <mxGeometry relative="1" as="geometry"/>
                 </mxCell>
-                <mxCell id="123" value="next" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="123" value="next" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
                     <mxGeometry x="680" y="520" width="120" height="40" as="geometry"/>
                 </mxCell>
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+                <mxCell id="124" style="edgeStyle=none;html=1;exitX=0;exitY=0.5;exitDx=0;exitDy=0;entryX=1;entryY=0.5;entryDx=0;entryDy=0;fontColor=#000000;" parent="1" source="125" target="120" edge="1">
                     <mxGeometry relative="1" as="geometry"/>
                 </mxCell>
-                <mxCell id="125" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="125" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
                     <mxGeometry x="680" y="560" width="120" height="40" as="geometry"/>
                 </mxCell>
-                <mxCell id="126" value="" style="edgeStyle=segmentEdgeStyle;endArrow=classic;html=1;curved=0;rounded=0;endSize=8;startSize=8;entryX=0;entryY=0.5;entryDx=0;entryDy=0;exitX=1;exitY=0.5;exitDx=0;exitDy=0;" edge="1" source="138" target="119" parent="1">
+                <mxCell id="126" value="" style="edgeStyle=segmentEdgeStyle;endArrow=classic;html=1;curved=0;rounded=0;endSize=8;startSize=8;entryX=0;entryY=0.5;entryDx=0;entryDy=0;exitX=1;exitY=0.5;exitDx=0;exitDy=0;" parent="1" source="138" target="119" edge="1">
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@@ -301,7 +301,7 @@
                         </Array>
                     </mxGeometry>
                 </mxCell>
-                <mxCell id="127" value="" style="edgeStyle=segmentEdgeStyle;endArrow=classic;html=1;curved=0;rounded=0;endSize=8;startSize=8;exitX=0;exitY=0.5;exitDx=0;exitDy=0;entryX=1;entryY=0.5;entryDx=0;entryDy=0;" edge="1" source="120" target="139" parent="1">
+                <mxCell id="127" value="" style="edgeStyle=segmentEdgeStyle;endArrow=classic;html=1;curved=0;rounded=0;endSize=8;startSize=8;exitX=0;exitY=0.5;exitDx=0;exitDy=0;entryX=1;entryY=0.5;entryDx=0;entryDy=0;" parent="1" source="120" target="139" edge="1">
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                         <mxPoint x="960" y="580" as="targetPoint"/>
@@ -313,48 +313,48 @@
                         </Array>
                     </mxGeometry>
                 </mxCell>
-                <mxCell id="128" value="INIT_LIST_HEAD(&amp;amp;ple-&amp;gt;list)&lt;br&gt;list_add(&amp;amp;ple-&amp;gt;list, &amp;amp;my_list)" style="edgeLabel;html=1;align=center;verticalAlign=top;resizable=0;points=[];fontColor=#000000;labelPosition=center;verticalLabelPosition=bottom;" vertex="1" connectable="0" parent="127">
+                <mxCell id="128" value="INIT_LIST_HEAD(&amp;amp;ple-&amp;gt;list)&lt;br&gt;list_add(&amp;amp;ple-&amp;gt;list, &amp;amp;my_list)" style="edgeLabel;html=1;align=center;verticalAlign=top;resizable=0;points=[];fontColor=#000000;labelPosition=center;verticalLabelPosition=bottom;" parent="127" vertex="1" connectable="0">
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                 </mxCell>
-                <mxCell id="129" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" vertex="1" parent="1">
+                <mxCell id="129" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" parent="1" vertex="1">
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                 </mxCell>
-                <mxCell id="130" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" vertex="1" parent="1">
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                     <mxGeometry x="680" y="600" width="120" height="50" as="geometry"/>
                 </mxCell>
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                 </mxCell>
-                <mxCell id="131" value="next" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="131" value="next" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
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                 </mxCell>
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                     <mxGeometry relative="1" as="geometry"/>
                 </mxCell>
-                <mxCell id="133" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
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                 </mxCell>
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                 </mxCell>
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                 </mxCell>
-                <mxCell id="138" value="next" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="138" value="next" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
                     <mxGeometry x="960" y="520" width="120" height="40" as="geometry"/>
                 </mxCell>
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                     <mxGeometry relative="1" as="geometry"/>
                 </mxCell>
-                <mxCell id="139" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" vertex="1" parent="1">
+                <mxCell id="139" value="prev" style="rounded=0;whiteSpace=wrap;html=1;" parent="1" vertex="1">
                     <mxGeometry x="960" y="560" width="120" height="40" as="geometry"/>
                 </mxCell>
-                <mxCell id="140" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" vertex="1" parent="1">
+                <mxCell id="140" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" parent="1" vertex="1">
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                 </mxCell>
-                <mxCell id="141" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" vertex="1" parent="1">
+                <mxCell id="141" value="" style="rounded=0;whiteSpace=wrap;html=1;labelBackgroundColor=#000000;fontColor=#FFFFFF;fillColor=#FFFFFF;" parent="1" vertex="1">
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             </root>
diff --git a/img/lectures/list_evolution.svg b/img/labs/list_evolution.svg
similarity index 100%
rename from img/lectures/list_evolution.svg
rename to img/labs/list_evolution.svg
diff --git a/labs/kernel_api.rst b/labs/kernel_api.rst
index 37d6c8d..3d9a18e 100644
--- a/labs/kernel_api.rst
+++ b/labs/kernel_api.rst
@@ -224,7 +224,7 @@ printk
 
 列表的演变可以在下图中看到：
 
-.. image:: ../img/list_evolution.svg
+.. image:: ../img/labs/list_evolution.svg
    :width: 1000px
 
 从上面的例子可以看出，通过 :c:macro:`list_add` 宏引入了堆栈类型的行为，并使用了标记。