<#assign x = pp.newWritableHash(stuff)>
<@pp.set hash=x key='c' value='C' />
<#assign y = pp.newWritableHash(x)>
<@pp.set hash=y key='d' value='D' />
<#assign z = pp.newWritableHash({'x':'X'})>
<@pp.set hash=z key='z' value='Z' />

stuff:
<@listMap stuff />

x:
<@listMap x />

y:
<@listMap y />

z:
<@listMap z />

<#macro listMap map>
  <#list map?keys?sort as k>
  - ${k} = ${map[k]}
  </#list>
</#macro>