The Names
Why are there eight trees here? It seemed a good option for presenting them for my children. See the blog post on Eight Surnames.
First, my eight, in couples, listed roughly from oldest to youngest. Then, my wife’s eight.
Mary Black (~1851 – 1919) & Rev. William Stevenson (1853 – 1888)
Williamina Laughland (1852 – 1945) & James Scobbie (1853 – 1943) – see for example here
Sarah MacMillan (~1854 – 1934) & James McKinnon (~1840 – 1927)
Jane Livingston (~1858 – 1917) & Colin Black (1850 – 1924)
Louisa Coupar (~1869 – 1947) & John Spence (1875 – 1923)
Agnes Inglis (1877 – 1946) & James Hay (~1878 – 1965)
Mary McLaughlan (~ 1877 – >1954) & Thomas Erskine (~1874 – >1954)
Isabella Kinnis (1887 – 1962) & unknown
The trees
These eight trees capture the recent past of our ancestry, the lowest rung being two generations back from me, my siblings, cousins, wife, and so on. The trees will present the binary ancestry as far as I know it of my children’s eight surnames (three generations back from them).
Four of the trees relate to my maternal and paternal families (“his”), four to those of my wife, their mother (“hers”). The only non-ancestors included are the siblings of the four + four grand-parents on the bottom rung.
The trees themselves are dated, so that anyone who downloads one can check for a better, newer version, available when I add information or correct errors. Relatives might want to contact me for more readable PNG or PDF of copies the ones relevant to them, because the graphics are not so readable online, especially on a phone or small tablet. (You can try re-opening each one in a new window.) Of course, making better trees with more and different information is also possible. These eight trees start some time in the past already in order to omit living people. Nobody mentioned here was born after 1910, and nobody is living.
Given the extensive information available on the internet (including on living people), I’ve included some links to GENi.com to exemplify what’s out there in black and white. The amount of information is growing, is not under your own control, and is not always accurate. A lot of information on living people is also available on social media etc.

Mary Black (~1851 – 29/9/1919) & William Stevenson (17/3/1853 – 13/98/1888). Glasgow and Dundee. Parents of Elizabeth Bertie Stevenson, my paternal grandmother (6/2/1883 – 26/12/1949). Public trees on GENi.com for Stevenson.

Williamina Laughland (31/3/1852 – 3/7/1945) & James Scobbie (20/7/1853 – 23/11/1943). Newarthill, Lanarkshire. Parents of George Hill Scobbie, my paternal grandfather (28/12/1881 – 11/5/1961. Public trees on GENi.com for Laughland and Scobbie

Sarah MacMillan (~1854 – 1934) & James McKinnon (~1840 – 1927). Balivanich, Benbecula (Baile a’ Mhanaich, Beinn nam Fadhla). Parents of my maternal grandmother Euphemia MacKinnon. Public tree on GENi.com (to appear)

Jane Livingston (~1858 – 1917) & Colin Black (1850 – 1924). Lismore (Lios Mòr), Argyll. Parents of my maternal grandfather Duncan Black. Public tree on GENi.com

Louisa Coupar (~1869 – 1947) & John Spence (1875 – 1923). Kingsbarns and St. Andrews, Fife. Parents of my wife’s grandparent. Public tree on GENi.com

Agnes Inglis (1877 – 1946) & James Hay (~1878 – 1965). Stewarton, Ayrshire. Parents of my wife’s grandparent.

Mary McLaughlan (~ 1877 – >1954) & Thomas Erskine (~1874 – >1954). Ayrshire.
Parents of my wife’s grandparent.

Isabella Kinnis (1887 – 1962). Kirk O’Shotts.
Mother of my wife’s grandfather. Public tree on GENi.com