The evil ruling party, the Liberatives, are redistributing the electoral regions (ridings) in your city, and are nefariously attempting to pack certain opposition-friendly neighborhoods into as few ridings as possible. If this plan succeeds, it will be the end of democracy as we know it! As a card-carrying member of the noble, compassionate Conservals (the main opposition party), you must foil their devious plot and safeguard the future of our country.
Under the new plan, the city will be divided up into a grid of rectangles by selecting certain major streets and avenues as boundaries. All streets and avenues stretch straight across the city, and are numbered starting from the southwest corner of the city. The city is bounded by four roads: 1st Street (west edge), 100th Street (east edge), 1st Avenue (south edge), 100th Avenue (north edge). Clearly these four roads must represent district boundaries; however, only a subset of the streets and avenues in between will divide districts. The Liberatives have already been able to fix the North-South (street) boundaries; however, they have been forced to allow the Conservals to select the East-West (avenue) boundaries.
You know the location of all the opposition-friendly neighborhoods, which vote strongly Conserval. A neighborhood is exactly one block between adjacent streets and avenues. For instance, one neighborhood might lie between 47th and 48th Street and 67th and 68th Avenue. Place the avenue boundaries so that as many ridings as possible contain at least one opposition-friendly neighborhood.