Select an existing directory that has only the inherited and explicit permissions you want to check for, or create a new one at search root to use as a test pattern. 

The script will create a permisson list of the  permissions on that folder as sddl, then compare the permission list in the directories in the specificed root to see if they contain those permissions.  If any of the permissions do not appear in the ACL for that directory, it will be write a message to the console that the permission inheritance on that directory is blocked.

$pattern_dir = "<pattern dir>"
$pat_sddl = (get-acl $pattern_dir).sddl
$root_dir = "<root folder dir>"

$sddl_aces = @()
$sddl_match = [regex]::Matches($pat_sddl,"(\(.+\))")
$sddl_match |% {
$_.value.split(')') |% {if ($_){$sddl_aces += ($_ + ')')}}

$dirs = gci $root_dir -Recurse |? {$_.psiscontainer}

foreach ($dir in $dirs){
$dir_sddl = (Get-Acl $dir.fullname).sddl
foreach ($sddl_ace in $sddl_aces){
 if ($dir_sddl -notmatch $sddl_ace){
 Write-Host "Blocked inheritance found on $($dir.fullname)"