58 draws an circular arc. The syntax is
#alltt150#
<#157#>diameter<#157#> is specified in 59 and both <#158#>start-angle<#158#> and <#159#>end-angle<#159#> are in radian. <#160#>start-angle<#160#>
must be within 0 and 2π and <#161#>end-angle<#161#> can be any value
between <#162#>start-angle<#162#> and <#163#>start-angle<#163#> + 2π. Arcs
are drawn in clockwise direction with angle 0 pointing to the
right on the paper.