DOT (Graphviz) source:

digraph TexAndFriends {
	subgraph cluster_engines {
		label = "Engines";
		// style=filled;
		// color=lightgrey;
		node [/*style=filled,color=blue,*/shape=rectangle];
		tex [label="TeX"];
		etex [label="eTeX"];
		pdftex [label="pdfTeX"];
		subgraph cluster_unicode_engines {
		    label = "Unicode";
		    xetex [label="XeTeX"];
		    luatex [label="LuaTeX"];
		    // luahbtex [label="LuaHBTeX"];
		    // lmtx [label="LMTX"];
		}
		tex -> etex -> pdftex;
		etex -> xetex;
		pdftex -> luatex// -> luahbtex;
		// luatex -> lmtx;
	}
	
	subgraph cluster_formats {
		label = "Formats";
		node [style=filled, shape=house];
		plain [label="plain"];
		latex [label="LaTeX"];
		context [label="ConTeXt"];
		{rank=same;rankdir=LR;
		plain -> latex -> context [style=invis];
		}
	}
	
	/*
	subgraph cluster_otherengines {
	    label = "Other engines";
	    node [shape=rectangle];
	    lmtx [label="LuaMetaTeX"];
	    luahbtex [label="LuaHBTeX"];
	    {rank=same; rankdir=LR; pdftex -> luahbtex [style=invis];}
	}
	*/
	
	subgraph cluster_cli {
	    label = "Command-line shortcuts (commands) in TeX Live\nEach command = some engine + some format";
	    othercommands [label="Others:", shape=note];
	    texcmd [label="tex"];
	    pdftexcmd [label="pdftex"];
	    xetexcmd [label="xetex"];
	    luatexcmd [label="luatex"];
	    contextcmd [label="context"];

	    latexcommands [label="LaTeX format:", shape=note];
	    latexcmd [label="latex"];
	    pdflatex;
	    xelatex;
	    lualatex;
	    
	    luatex -> latexcommands [style=invis];
	    {rank=same; rankdir=LR;
	    latexcommands -> latexcmd -> pdflatex -> xelatex -> lualatex [style=invis];}
	    {rank=same; rankdir=LR;
	    othercommands -> texcmd -> pdftexcmd -> xetexcmd -> luatexcmd -> contextcmd [style=invis];}
	    
	    {edge[style=invis];
	    lualatex -> luatexcmd;
	    latexcmd -> texcmd;
	    pdflatex -> pdftexcmd;
	    xelatex -> xetexcmd;
	    }
	}
}

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