Alleys exist between some of the buildings.   I will either (a) make buildings with alleys wider apart from each other, or (b) have an arrow or footprints in the alley to indicate Holmes can take an alley.  The footprints idea is shown in this city street screen, 2 little yellow foot prints:  

Alleys will look similar to below. This is a real picture in Antic4.  It is my draft #1 of an alley screen and I think it already looks close to what I imagined.  I still need to replace the very bottom with the DP information panel with the gauge and color clue categories.    I'm trying to be economic in the amount of unique character set tiles I'm using for alley screens, since alleys and City Street screens currently share the same charset.    

Alleys serve a couple of purposes in Atari 5200 Detective Powers.    

1.  They can be a shortcut between streets. Shortcuts won't use any juice from your Detective Powers gauge.  But if you walk to the end (left or right) of a street to go up or down to the next street, you'll use a little bit of DP each screen change.   

2. Alleys can have Pubs which Holmes can enter. He may find a person to interview to solve a Color Clue.   OR he may find a helpful item like a cup of coffee to boost his DP gauge.     OR he may enter and it could have a Thug that he'll need to escape. 

3. Alleys may have other dangers like Dogs or Thugs.   If they attack Holmes (touch him), you'll lose some of your DP gauge.  Study their walking patterns to get past these dangers without penalty.